The motor in my Yukon grenaded.

[osteodoc08]

Wife's 2013 Yukon Denali motor is toast. She was driving to pick up her sisters dress when it started knocking. I told her to pull over and stop motor. I picked her up and then later got it on my car hauler. It sound like it had spun a bearing or dropped a rod.

Dealer confirmed it today. They went to pull it into a service bay and the rod puked out the bottom along with the oil. 64k miles on it. Never towed with it. Always kept up with oil changes with castrol syn blend or whatever they're calling it now and an ac/delco filter. Had it changed once at a Goodyear tire center out of convenience when I got new tires put on.

New motor on its way. Hope GM covers entire bill. Wife threw out a few of the oil receipts and I had just changed the oil about 1000 miles ago. Oil was full with no loss of coolant when I checked it out when I first went to get it.

Disappointed to say the least.

[Artful]

Is that the 5.3L Vortec V8?

[Eddie17]

They have 100,000 mile drive train warranty right!
130,000 plus on my 2004 with no motor problems.

[osteodoc08]

6.2L motor. Always used premium grade gas and spec oil and ac delco filters. I don't get it.

[JeffinNZ]

64K is only just run in for a big eight.

Our diesel SUV died in spectacular fashion 18 months ago. Still, it was 18 years old and we had had 7 good years out it. Still hate it.

[country gent]

2001 Excurrsions tranmission is going 7.2 diesel is going great yet. Doubt fords will do anything at 190,000 miles LOL. To big to make a flower box out of .

[project]

The 6.2 is a tough motor and if it failed I seriously doubt it was anything you did. Dealer should replace it without any problems. It's the same basic motor that's in the CAMARO and corvette with a different intake and cam.

[Lloyd Smale]

I know they had some problems with the last gen 5.3 with oil consumption and even some premature failing and that's why they totally redesigned there motor in 14. Ive never heard of problems with the 6.2 though. they might get a bit persnickety with you if you haven't been running synthetic in it.

[dubber123]

Synthetic is good. I still don't buy their super high change intervals, but I'd expect to get more than 64,000 miles out of ANY vehicle, much less an expensive one. Almost 270K on my daily bomber, using conventional Castrol oil.

That engine had a problem the day it left the factory. I'm guessing oil pump failure. A bearing or crank issue would have shown up much sooner.

[oldred]

When you consider how many engines are out there in daily use, some with even poor maintenance, the over-all reliability record is amazing and it would be all but impossible to totally eliminate failures such as this. Apparently what happened is you got one of the very rare ones to leave the factory with a mechanical defect, it IS going to happen sometimes, and while it may be disappointing to be the lottery "winner" this time it's just part of the deal we accept when we buy a new vehicle. That's what warranties are for and unless that engine has been obviously and shamelessly neglected and abused (which quite clearly it has not!) then the warranty should make things good again!

BTW if that engine does not have a specific requirement for premium fuel then over it's lifetime the wasted fuel expense is substantial! Premium fuel is no different than regular grades except for the anti-knock level and unless the engine knocks on lower octane fuel there is no benefit what-so-ever to using premium. The oil companies have done a great job of perpetrating this "premium is better" myth but it is that a myth!

[osteodoc08]

Oldred, premium is specified for this motor. My daily driver car gets plain ole regular. I've had 105k trouble free miles and counting on it (2011 Chevy Malibu) Id love to break 250k with it.

[SeabeeMan]

I would think they'd cover the full bill. We just bought a Corolla and I specifically asked about doing my own oil changes since we are 80 miles from the dealership. I explained that I buy my filters by the case and oil by the 5 gallon bucket so receipts weren't going to make much sense. They told me not to worry about it and that customer receipts don't mean much anyways if somebody is trying to prove something one way or the other.

I confirmed this with the maintenance and warranty manager later that week and he explained that due to a law he cited about warranty coverage (can't remember the name), they have to prove that a customers actions, or lack thereof, CAUSED the failure, which is basically impossible unless the crankcase is dry as a bone or the filter is missing. Anything beyond those obvious things and it is nothing I have to worry about.

[osteodoc08]

Magnusson-Moss is what you're thinking of.

[Minerat]

2000 6.0l with 208,000, still pulls the 10000 lb utility trailer over Vail pass at 65 mph. Use Mobile 1 and change it religiously every 18000 mile wheather it needs it or not. Sometimes you are just unlucky hope they get you up and running soon.

[jmort]

6.0 are great engines

[DougGuy]

I usually change out full synthetic at 8,000mi. By then it's plenty dark and that's enough reason to change it in my book.

Otoh, we have a 2001 Dodge Ram 3500 RV with the mouse motor, the 5.2L magnum. They had enough sense to put 410 gears in it so it gets on up pretty good on the interstate, but the oil is getting dark at 4,000mi. Considering the gear in the back of it, this one will likely get oil changes at 4,000 or 5,000mi. That's probably close to the same amount of engine revolutions as 8,000mi on regular gearing in the differential.

Hope they treat you right on the 6.2 OP, sounds like these are a decent little stroker motor.

[cajun shooter]

I always use full sythenic in my GMC Diesel but I change it out at 4000 mile interval. I also use WIX filters. At one time I was a solid Fram man but they went to very cheap insides and make them offshore. Wix is the top rated filters across the board.
My odometer just turned 135,000 and the motor is the same as the first day she was cranked over.
They do have motors that slip by final inspections. I purchased a new 1974 Monte Carlo that used a quart of oil every 500 miles. They told me is was just breaking in. I had graduated from a federal Government mechanic school and knew that was a bunch of BS.
They found out after I left the car blocking the shop doors and locked up that the motor had a defect from the factory. The right side head had no oil drain holes that allowed the oil to drain back into the crankcase. The valve cover was filling with oil and it was going by the valve seals and out the exhaust.
They can make mistakes but the GM small blocks are the best design motors to ever be built.

[KAF]

When GM assembled their engines instead of using gaskets, some type of silicon of other kind on gel like substance. That **** was known to leak at the intake. Dex cool would leak down to the oil pan, impregnate bearings and they would fail without warning, no matter how well maintained the engine was.
I'd bet dollars to donuts that was the problem.......do not ask how I know....

[Kent Fowler]

Oldred, premium is specified for this motor. My daily driver car gets plain ole regular. I've had 105k trouble free miles and counting on it (2011 Chevy Malibu) Id love to break 250k with it.

My 2011 6.2L Silverado got better mileage using the mid range 89 octane gas for some reason. BIL is one of the managers for the emergency services for Houston tollway and has over 100 vehicles, including tow trucks, with the 6.2 in them. He said the county contracts for the cheapest priced 89 octane gas and they have never experienced any performance or mechanical problems using it in the 5 or so years they have been putting it in their vehicles. Don't know why GM specifies premium in that engine.

[MT Gianni]

BTW if that engine does not have a specific requirement for premium fuel then over it's lifetime the wasted fuel expense is substantial! Premium fuel is no different than regular grades except for the anti-knock level and unless the engine knocks on lower octane fuel there is no benefit what-so-ever to using premium. The oil companies have done a great job of perpetrating this "premium is better" myth but it is that a myth!


2008 Outback got 3 mpg higher with midgrade than bottom grade fuel. Plugs went out after 15,000 miles on low grade.

[TXGunNut]

The 6.2 is a better engine than that, you just got a bad one. You'll have better luck with the next one.

[oldred]

Oldred, premium is specified for this motor. My daily driver car gets plain ole regular. I've had 105k trouble free miles and counting on it (2011 Chevy Malibu) Id love to break 250k with it.


When premium is specified then it certainly is required and regular should be used only in an emergency! This premium vs regular thing has been an on-going argument for years and I suppose it will remain so but the fact is for most folks untold thousands of dollars are wasted buying higher octane than they need. Fuel costs are a major concern for a lot of people and it's just the oil companies have bilked the pubic for millions and I hate to see folks falling for the scam. There is no scientific reason for premium fuel to yield better mileage in a properly functioning engine designed for regular but it's been estimated that fully 40% of drivers mistakenly believe that premium gives better mileage and more power when it's simply not true, in your case however with that engine regular grades are not an option.

[dubber123]

2008 Outback got 3 mpg higher with midgrade than bottom grade fuel. Plugs went out after 15,000 miles on low grade.

My Subaru and my girlfriends both get enough better mileage with mid grade than regular to be the cheaper option. I have a finely tuned ear for spark knock, and I can hear it under load with the cheap stuff in mine, as well as her last 2, even though the Mfg. calls for regular. I, and a friend of mine had Corollas that were the same way. I have close to 270K on mine, and if it had been spark knocking on the cheap stuff this whole time, I doubt I would have made it this long, and still have a quiet running engine that uses maybe 1/2 quart between changes.

The OP unfortunately got a bad engine. My former employer regularly gets 200,000+ from his Chevrolets, and had one puke on them 2,500 miles from home with only 15,000 miles on the brand new vehicle. The replacement engine is over 200,000 and still going.

[oldred]

There's no point in arguing about the premium vs regular because those that think they get better power and mileage will never be convinced however it's only their money they are wasting. Slightly better mileage/power from different blends (different brands) or even from Summer vs Winter blends are possible but simply between higher octane fuels is not going to happen for most vehicles because there simply is no reason for it! Both fuels contain the same amount of energy and there is absolutely nothing in premium fuel to make more power, it would need to make more power to improve mileage, the higher grades only contain more anti-knock additives that slow down the burn rate. There are hundreds of web sites that explain in detail and warn folks but few are willing to listen, premium costs more and high performance engines use it so it must be better right? Well yes IF your engine has a high enough compression ratio and timing curve to cause detonation on the lower grades but few engines these days fit that description. Switching to mid grades can sometimes help with a knock problem but often as not simply switching brands can accomplish the same thing or sometimes switching to the higher grade simply masks a problem with the engine that should be corrected. Here is one of hundreds of sites that attempt to explain but the oil companies have done a magnificent job over the years of convincing people to buy their inflated price product and most are not about to change,

http://www.cartalk.com/content/premium-vs-regular-0

Googling this question can be a real eye opener!

Let's take a look at a car that gets 25 MPG and thirty cents difference between fuel grades (what it is here locally)

100,000 miles divided at 25 MPG would take 4000 gallons of fuel and cost an extra $1200 or an extra $600 for 50,000 miles, that's not exactly an insignificant difference! Folks who claim their vehicles would die early from using regular are ignoring the identical ones around that run just fine on regular. The gas companies are fond of posting slogans like "Feel the power" (of what?) or "Better mileage on XXXX super premium" but better mileage than what? Never ever will you see better mileage with our premium vs our regular because it would be a lie they would get busted for PDQ! If they actually could claim better mileage with premium they would jump all over that and plaster the pumps with the ads but you don't see claims like that, wonder why?

[waksupi]

There's no point in arguing about the premium vs regular because those that think they get better power and mileage will never be convinced however it's only their money they are wasting. Slightly better mileage/power from different blends (different brands) or even from Summer vs Winter blends are possible but simply between higher octane fuels is not going to happen for most vehicles because there simply is no reason for it! Both fuels contain the same amount of energy and there is absolutely nothing in premium fuel to make more power, it would need to make more power to improve mileage, the higher grades only contain more anti-knock additives that slow down the burn rate. There are hundreds of web sites that explain in detail and warn folks but few are willing to listen, premium costs more and high performance engines use it so it must be better right? Well yes IF your engine has a high enough compression ratio and timing curve to cause detonation on the lower grades but few engines these days fit that description. Switching to mid grades can sometimes help with a knock problem but often as not simply switching brands can accomplish the same thing or sometimes switching to the higher grade simply masks a problem with the engine that should be corrected. Here is one of hundreds of sites that attempt to explain but the oil companies have done a magnificent job over the years of convincing people to buy their inflated price product and most are not about to change,

http://www.cartalk.com/content/premium-vs-regular-0

Googling this question can be a real eye opener!

Let's take a look at a car that gets 25 MPG and thirty cents difference between fuel grades (what it is here locally)

100,000 miles divided at 25 MPG would take 4000 gallons of fuel and cost an extra $1200 or an extra $600 for 50,000 miles, that's not exactly an insignificant difference! Folks who claim their vehicles would die early from using regular are ignoring the identical ones around that run just fine on regular. The gas companies are fond of posting slogans like "Feel the power" (of what?) or "Better mileage on XXXX super premium" but better mileage than what? Never ever will you see better mileage with our premium vs our regular because it would be a lie they would get busted for PDQ! If they actually could claim better mileage with premium they would jump all over that and plaster the pumps with the ads but you don't see claims like that, wonder why?

I drive older vehicles, so use alcohol free gas in both. Premium is the only choice to get the alcohol free. I do get better mileage with the alcohol free, enough to make up the difference in cost per mpg. I mainly use it because I am still shy of any damage that may be done to older components by the alcohol.

[GaryN]

That ethanol free gas really does give your car better mileage. We have one station here that sells it. It costs quite a bit more but I use it in all my lawn equipment. A lot of my old motors on chain saws and such were made long before ethanol. Ethanol can really trash old fuel lines and even some gas tanks. I get about 3 miles per gallon extra on a tank of ethanol free gasoline in my F150 4x4.

[TXGunNut]

I understand the relationship between compression ratios and octane ratings but I seldom try to explain it. I once heard a trusted indy mechanic wax eloquent about "treating" a car with premium from time to time to keep it performing like it should. Yes, my air-cooled engines prefer higher octane fuel but the 4.6's under my carport are quite happy with 86 or 87 octane fuel, one will even burn E-85 if I could find it.

[KAF]

Although higher octane can cost substantially more per gallon, it does not necessarily mean it is better for your car. Higher octane gas is processed through additional steps that further refine the blend and cause it to burn more slowly than lower octanes. These additional processes are what contribute to the higher pricing, but that does not mean the higher octane will offer any advantage over other blends in many engines. Octane does not offer any better fuel mileage, increase engine horsepower, or make the engine start quicker. Higher octane only reduces the likelihood of engine knock or ping.

http://blog.hemmings.com/index.php/2014/04/11/tech-101-octane-the-facts-and-the-fiction-behind-those-higher-priced-fuels/

[oldred]

Alcohol blends do indeed get less mileage than either premium or regular grades of 100% gasoline blends but that's a whole 'nother story! The reason alcohol blends get less mileage (and make less power) is because there is not nearly as much energy in a gallon of alcohol as there is in gasoline so the more alcohol in the fuel the less power and mileage it will yield. Unless a gasoline specifically states 100% gasoline then the premium or regular is no different in that respect as both are usually blended at the same rates for a given brand. Here in our area there are only a handful of stations that even offer 100% gasoline and it is clearly advertised rather than just marked (as required by law) on the pump, however all but two of these offer stations offer 100% in the 89 octane mid-grade only while the other two offer it in both mid and premium grades. Here locally the price difference averages about 40 cents more for the 100% blends so that more than negates the cost savings making it more expensive to use, still for small air cooled engines such as lawn mowers and chain saws (and a lot of motorcycles!) it can be worth the extra cost to avoid problems alcohol can sometimes cause. So don't make the mistake of thinking that just because it's premium it is 100% gasoline because by far most premiums contain the same amount of alcohol, or maybe even more since alcohol is an anti-knock compound, as their regular grade brethren at the same pump station.

But again "gasahol" vs 100% gasoline has little or nothing to do with regular vs premium. Both regular vs premium contain the same detergents and other additives to keep injectors clean and keep down carbon buildup, this is mandated by federal law, with octane boosting additives being the difference between the two. Probably it's the high performance image that leads to most of the misconceptions about premium fuel, the premium fuel does NOT make a high performance engine make more power it simply ALLOWS the engine to make more power by allowing it to be designed to a higher state of tune. Without that extra compression, ignition timing/curve and or supercharger/turbocharger then that extra octane a person pays for is simply wasted. Actually it could be argued that higher than needed octane could result in LESS power and fuel mileage for an engine that doesn't need it! The reason is the extra additives to the gasoline slow down the burn rate and take up a part of the gasoline volume in each gallon and since most of the additive burn with less energy (or even none in some cases!) each gallon would contain less available energy. Of course such an argument, while it may be correct in principle, would just be silly since any losses would be so slight as to be hardly detectable but still any kind of loss is less than the gain that some believe they get.

[EDIT] I just read the link in the above post and here is something they too had to say about premium actually offering LESS, rather than MORE, miles per gallon,


The higher octane fuels are slightly less efficient than the lower grades because the retarded ignition will lead to a little less overall power and a scant fewer miles per gallon

Sorry for the fuel rant but we are all being gouged to the bone and have been for years by the oil crooks and it just galls me to see them get away with gouging people even more by a false and very misleading campaign to hawk their grossly over-priced premium fuels to those folks who simply don't need it. The consumer advocate groups and several other organizations have been screaming from the roof tops warning folks about this scam for years but most simply won't listen!

[rockrat]

I understand the regular vs premium thing and run regular in most all my vehicles. There are exceptions to the idea that use the cheapest fuel that won't ping. When timing was set by initial timing and centrifugal timing in the distributor that rule was good, but nowadays, computers can change timing as the engine is running. Some vehicles can benefit by increased octane as the engine can adjust the timing to take advantage of this. My Daughters VW Passat does so much better on premium, in increased mileage and driveability, that it actually offsets the extra cost. Same with the wifes Toyota, and my older Thunderbird Turbo Couple (which has a switch for when you use premium fuel). The wifes car does better on a mid-grade, which up here is 87 octane, and my Thunderbird does better on octane just shy of premium, by a point or two, but higher than mid-grade. My Toyota, however, higher octane fuel does nothing but cost more, so I don't run it. I do run non-alcohol gas in my lawn and garden equipment and my motorcyle even though they really gouge around here for it.

[freebullet]

It failed because it's built like a tinker toy as are most new vehicles. It's a sad state of affairs. They design them to be thrown away. Not a fan of plastic bumpers, engine parts, & cheap poor designs.

[oldred]

I understand the regular vs premium thing and run regular in most all my vehicles. There are exceptions to the idea that use the cheapest fuel that won't ping. When timing was set by initial timing and centrifugal timing in the distributor that rule was good, but nowadays, computers can change timing as the engine is running. Some vehicles can benefit by increased octane as the engine can adjust the timing to take advantage of this. My Daughters VW Passat does so much better on premium, in increased mileage and driveability, that it actually offsets the extra cost. Same with the wifes Toyota, and my older Thunderbird Turbo Couple (which has a switch for when you use premium fuel). The wifes car does better on a mid-grade, which up here is 87 octane, and my Thunderbird does better on octane just shy of premium, by a point or two, but higher than mid-grade. My Toyota, however, higher octane fuel does nothing but cost more, so I don't run it. I do run non-alcohol gas in my lawn and garden equipment and my motorcyle even though they really gouge around here for it.



This is another common misunderstanding about computer controlled vehicles which is of course most of them made in the last 30 years or so with most of that number of newer vehicles having this knock sensing feature. It might add up if the computer retarded the timing all the time the regular fuel was being burned but that's simply not the case, the timing is compensated ONLY when knocking is sensed but that would happen only a small fraction of the time the engine is running, hot under a heavy load such as during hard acceleration or pulling a heavy load uphill. If the engine is experiencing knock that causes the computer to change the ignition curve during regular driving (cruise conditions that account for the vast majority of driving) then there is a mechanical problem or the fuel is defective and even below it's standard rating, a condition that occurs more often than folks might imagine especially from cut-rate dealers but the solution there is to change dealers/brands. So yes it can be argued in principle that computer compensation can account for a difference but in reality the difference is small to begin with and when even that is spread out over the very small percentage of driving time that would require this compensation then even those possible gains are relatively insignificant and can not recover any significant extra costs for fuel.

BTW, the VW Passat REQUIRES premium fuel and as such does not fit into the description of the vehicles that would be wasting money on premium fuels. The vast majority of cars/trucks require only a regular grade and those are the ones who would be wasting money! Short of the high performance engines that REQUIRE high octane fuel and would suffer from performance issues due to spark knock/pre-ignition there simply is no way using premium fuel can lead to better mileage! It just doesn't work that way, both premium and regular grades have essentially the same BTUs per pound or energy per gallon, with regular actually having a very slight (VERY slight!) advantage over premium due to the slower burn rate and the non-energy containing additives of premium that make up a larger part of the gallon/volume (the above quote from Hemmings is just one of many discussing this)!

I know a lot of folks are convinced they are getting better mileage with premium but the physical means for this to happen is simply not there! In order for it to actually happen premium fuel would have to have a higher BTU per pound rating than regular grades but it does not, it's just simple laws of physics.

[MaryB]

Can't find gas without ethanol in my part of Minnesota, have to run it in the small engines etc. Have had it dissolve fuel lines too...

[oldred]

Can't find gas without ethanol in my part of Minnesota, have to run it in the small engines etc. Have had it dissolve fuel lines too...

That's a real problem for a lot of folks and was here too until fairly recently but now a few stations do offer 100% gasoline in the mid grades and a couple of them even have a 100% premium grade (in addition to the alcohol blend premium) but these are at inflated prices. No way can replacing the 10% by volume of alcohol account for 30 to 40 cents per gallon increase in price but still for certain uses it's worth the difference to prevent damage to equipment and in most cases of mowers, weed eaters, etc a person needs only a few gallons anyway.

[Petrol & Powder]

oldred- you rock !
octane ratings and compression ratios are a complete mystery to most folks. The analogy that I use when attempting to explain octane ratings is a ladder.

If you need a 10' ladder to get on the roof of your house then buy a 10' foot ladder. You can buy a 20' ladder if you want and it will work but it will cost more, be heavier be more difficult to carry and store and it does the same thing as the lighter, cheaper and shorter ladder. it's your money.


Now the ethanol/gasoline blend is a whole different argument. Bottom line, alcohol produces fewer BTU's per given volume than the same amount of gasoline. When you blend alcohol with gasoline you reduce the potential amount of power available in a given volume and you need to burn more to obtain the same level of power, therefore your fuel mileage will decrease when using gasohol vs. gasoline. That's not even getting into the effects of alcohol such as its affinity for water and what it does to some materials.

[oldred]

One of the myths that I especially get a kick out of is the idea that a person should buy a tank full of premium every third or fourth tank or so to "clean out the engine". Of course buying that tank full every third or fourth fill up only cleans out a person's wallet but like lot's of other fuel myths it's nearly impossible to get some folks to believe it.

One of the most telling things about the extra mileage from premium myth should be obvious but few if any even notice and that's the lack of claims by the oil companies that you will get better mileage by using premium vs regular, they simply will not make such a claim but why not? If it were true they would be hawking that claim on every pump but they don't, they will simply use vague slogans like "More miles (compared to what?) and a cleaner engine with Super clean premium" (even though the detergents and other cleaning agents are mandated by law for ALL grades!) or "Feel the power", as if you might feel a lack of power with regular maybe? You will never ever see or hear an ad from the oil companies claiming an advantage of a cleaner engine or better mileage by using premium vs regular grades! This is big business and the oil companies spend millions trying to part people with their hard earned money so slick ad campaigns are designed to make folks think octane equates to quality and performance, never mind all three grades are essentially the same thing but the more expensive grades simply have additives to slow down the burn rate. Never mind that if anything, because of this modified burn rate, folks may actually get LESS performance and mileage (although by only an insignificant amount) by using a higher than needed octane rating, they will continue to be duped into spending an extra 20 to 40 cents or so per gallon and be happy with it thinking they are taking better care of their cars/trucks and even saving money by spending more for something they simply don't need!


That ladder analogy is a good one! I will probably shamelessly steal that one from you sometime in the future!


One other little note about "gasahol", the alcohol content will be shown on the pump (usually on a tag on the side), this is MANDATED BY LAW and applies to all grades! Buying premium does not mean buying less alcohol and could mean getting an even steeper alcohol/gasoline mix because alcohol is a cheaper method of raising the octane level. In any case just look on the pump being used, most will say they contain "up to" 10% and you can bet they will usually go for the limit! This 10% blend (E10) is normally considered the limit that will be safe for all engines but of course higher blends can certainly be found all the way up to 85% alcohol (E85) however these pumps will be so marked. When determining the alcohol content of a gallon of gas simply ignore the premium/mid/regular designations and look at that all important tag on the pump, that is what will tell the tale!

[MaryB]

Between lawn tractor, snow blower, weed eater, 2 chainsaws, generator... I use about 30-50 gallons of gas a year in small engines so not having access to no alcohol is a real pain. Have to clean carbs yearly for example. Older fuel systems all had to be upgraded with better hoses...


That's a real problem for a lot of folks and was here too until fairly recently but now a few stations do offer 100% gasoline in the mid grades and a couple of them even have a 100% premium grade (in addition to the alcohol blend premium) but these are at inflated prices. No way can replacing the 10% by volume of alcohol account for 30 to 40 cents per gallon increase in price but still for certain uses it's worth the difference to prevent damage to equipment and in most cases of mowers, weed eaters, etc a person needs only a few gallons anyway.

[10x]

And that is why I now drive a Toyota Tundra assembled in San Antonio texas from U.S. made Toyota spec parts.
I purchased my last new Chev in 2008 - great gas mileage but mechanically unreliable and once off warranty expensive to repair.

[oldred]

And that is why I now drive a Toyota Tundra assembled in San Antonio texas from U.S. made Toyota spec parts.
I purchased my last new Chev in 2008 - great gas mileage but mechanically unreliable and once off warranty expensive to repair.

I have a buddy with a Tundra V8 and that engine is AWESOME! I would love to have one of those things just to play with!

[tomme boy]

The 5.3 oil use was because the oil return holes in the pistons were too small. So the pistons overheated and burned up the oil rings. That 6.0L is a bullet proof motor.

[historicfirearms]

Between lawn tractor, snow blower, weed eater, 2 chainsaws, generator... I use about 30-50 gallons of gas a year in small engines so not having access to no alcohol is a real pain. Have to clean carbs yearly for example. Older fuel systems all had to be upgraded with better hoses...

Go to your local small airport and buy some 100LL (100 low lead or avgas) and run it in your small engines before storage. It will last all winter or summer without going bad and gumming up your carbs. Or check at most marinas for ethanol free gasoline. These fuels cost more, avgas is $4.65 per gallon at my airport in Michigan, but its well worth it for avoiding the problems of ethanol blend fuel. One other thing, if you get some 100LL, do NOT put it in anything with a catalytic converter.

[oldred]

if you get some 100LL, do NOT put it in anything with a catalytic converter.


You got that right!!!!! Doing so will result in what a lot of folks learned the hard way back during the change-over to un-leaded gasoline. I too have used quite a bit of 100LL but the thing is our local airport is one of the few places here that also sells mid-grade auto gas in the 100% blend. Actually I think the "Low Lead" designation for Av-gas is kind of a misnomer when thinking in terms of auto gas (as is the octane rating for that matter) since it is Low Lead relative to other aviation grades and actually contains about as much lead and possibly even a bit more than the old leaded auto gas from years ago. In any case trying to burn it in anything with a Catalytic converter will result in serious damage! I have heard, back in the day when both were available, that it won't hurt to burn a little leaded gas with a catalytic converter occasionally but that was because the damage didn't usually become apparent immediately. Burning even a small amount causes serious damage and starts the decline of the catalyst and will result in a clogged converter in a fairly short time even if no more leaded gas is used.

[rockrat]

oldred--
The Passat may require premium fuel, but not at the altitude where we live. Compression ratios are degraded the higher up in altitude you go, unless you have a turbocharged engine, which my daughter does not. You lose about 3% performance in an unturbocharged engine per thousand feet, so we lose 15-20% horsepower up here. I would suspect C/R is lost at about the same rate, so instead of, say 9.5 to 1 ratio, it drops to 7.5 - 8.0 to 1. Our regular is only 85 octane.

[oldred]

Being an airplane pilot I am very familiar with altitude/power loses as well as turbo and supercharged engines, so yes I can certainly agree that altitude makes a difference. Also my comments were not (with the exception of the mention of the Passat) aimed at you but rather just comments about fuel and engine function in general, I think after re-reading my post I may have come across as being argumentative but that was not at all my intention and I want to apologize for not wording that better.


What I was really commenting on is the very widespread misconception about using regular vs mid-grade fuels in vehicles with knock sensors that will retard timing and in some cases modify the fuel mixture to compensate for inadequate knock suppression abilities of the fuel in the tank, at ALL other times the engine will run in the same mode with either fuel. The common line of thought is that if the octane is to low then the computer will compensate resulting in the engine running at less than optimum performance and thus getting less mileage making the more expensive fuel cheaper to use. On the surface this may seem to be logical BUT when looking at what is actually happening it just doesn't add up, not even close. For that to actually occur the computer would have to somehow know what the octane rating was on the fuel being fed to the engine and make the necessary compensation until the fuel was changed but of course that's not what happens and it would be very wasteful if it did. What really happens is that in the very small percentage of the time that the engine is under the kind of load that can cause knock to be encountered (in a properly functioning engine) the computer will sense the spark knock with the knock sensor (usually located on the side of the block) and briefly compensate for this condition. As soon as the compensation is made the knock will cease and the computer will, after a few seconds, revert back to the normal setting and stay there as long as the knock is not being detected so the actual percentage of the time the engine is running in compensation mode vs running normally is quite small indeed and even then any economy losses are going to be slight especially when it's considered that the compensation mode is only encountered in high load low economy conditions anyway.

The bottom line is it's much cheaper to use the less expensive fuel and allow the computer to run in the normal mode the vast majority of the time the engine is running and make those minor and quite brief adjustments only when needed. The alternative is to pay the extra 20 cents or so per gallon for 100% of the time the engine is running even the vast majority of the time when not needed as opposed to allowing the computer to compensate (at a rate probably even below 20 cents per gallon!) only during the brief times it is needed! The bottom line is that there simply is no way a few seconds here and there of computer compensation for regular vs mid-grade for a properly operating engine is going to over-ride anywhere near a 20 cents per gallon price difference.


We also need to look at why this compensation system is being used in the first place. The auto manufacturers are hard pressed to meet the CAFE requirements for fuel mileage as mandated by Government regulations. They could easily build the engine to run in all normal operating conditions without encountering spark knock but to do so would hurt fuel economy. They could just as easily build the engine to get the better fuel mileage but the economy would be more than offset by the extra octane requirement required to deal with the occasional engine ping that might result. Meeting the CAFE requirements would be a lot easier if all cars and trucks were designed to use premium fuels but buyers would be put off by the higher fuel costs of either premium or even mid-grade fuel. The solution was design the engine to higher specs that would normally require a higher octane to be certain to meet all driving conditions but to equip this engine with a system that would allow it to use the lower grade fuel for the vast majority of driving conditions where either fuel works equally well but still be able to deal with the occasional adverse situation that might result in knocking with the lower octane fuel, this system works well and is being used more and more on newer vehicles.

The idea is to allow the higher performance and better mileage normally associated with engines requiring a higher grade of fuel but while still being able to take advantage of the cheaper fuel, however by opting for the higher grade fuel anyway money is wasted because the system intention is being defeated!

[10x]

When premium is specified then it certainly is required and regular should be used only in an emergency! This premium vs regular thing has been an on-going argument for years and I suppose it will remain so but the fact is for most folks untold thousands of dollars are wasted buying higher octane than they need. Fuel costs are a major concern for a lot of people and it's just the oil companies have bilked the pubic for millions and I hate to see folks falling for the scam. There is no scientific reason for premium fuel to yield better mileage in a properly functioning engine designed for regular but it's been estimated that fully 40% of drivers mistakenly believe that premium gives better mileage and more power when it's simply not true, in your case however with that engine regular grades are not an option.

Depending on the location of the gas station just because it says 91 octane on the pump does not mean you are getting 91 octane or quality fuel.
I keep track of my fuel mileage tank by tank. On long trips I will buy gas at specific service stations - In British Columbia it will be a Chevron Station and the fuel with be 91 octane with Techron. Usually gas milage is stellar in my Tundra usually between 22 and 24 miles to the U.S. gallon. Get a tank of bad gas and mileage will drop to 15 mpg or less - some service stations have fuel that consistently gives lower mileage.
In Canada I have got the best mileage from Shell premium - consistently, then from Petro can Premium and usually from Chevron premium - although mileage will vary depending on which Chevron station I purchase fuel from.
If I purchase fuel with 5% ethanol, my mileage drops 7% or more, The more ethanol in the fuel, the more the mileage drop.
This is from my 5.7 L Tundra and I have kept track of mileage with every tank of gas purchased over 70,000 miles since it was new in 2011

[oldred]

I have no idea what Canadian laws are governing fuel sales so I can't comment on the substandard octane problem, here in the States the octane is regulated by law and if (when!) a person runs into that problem it's actually an illegal situation. It is an error at the refinery and they can be fined heavily for selling fuel that has an octane level below the rating but still it does happen occasionally. Even with the lower grades there is no reason at all for the regular grades to get less mileage than premium UNLESS the engine is pinging constantly, or nearly so, on it. There is absolutey nothing in Premium fuel to make more power or mileage and in fact as has been stated before (also check the link to Hemmings) regular grades should actually provide a very slight improvement over premium (unless pinging occurs frequently) because of the additives in premium. This difference is so slight as to be a non-issue however but the point is there is the same BTU content in a gallon of gas regardless of the grade. The only thing the premium does is raise the point at which detonation will occur and unless detonation is being encountered there is no difference at all and both grades will perform exactly the same! Again I don't know what Canadian laws are concerning detergents/cleaners in gasoline blends but here it is mandated by law for ALL grades but even at that additional detergents/cleaners equate to LESS mileage instead of more because they take up volume but do not add power.


As I pointed out before if there were advantages to premium over regular that resulted in better mileage or cleaner injectors the oil companies would be shouting it from every station! They would proclaim how much better their premium is compared to their regular and we would be looking at such ads plastered all over the pumps at every station but NEVER, EVER do we see that, wonder why? Oh sure there are the catch phrases mentioned before proclaiming how clean burning the premium is but they won't mention that the regular is the same (mandated by law here) rather they just lie by omission and let the customer draw his/her own conclusions. They will say things like "Get better performance and mileage with our super premium" (but they don't say what it's better than), NEVER, EVER will you see a dealer proclaiming that you can get better mileage with their premium vs their regular, NEVER! The reason is they can't because it doesn't work that way and as much as they want people to believe such a thing they know it's not true so they can't (and don't!) say it.

They can get away with inflated claims and brags about their products as long as they are not comparing them so ads are chosen carefully so as to mislead customers but not incriminate the seller! This is just normal marketing practice for almost everything has been going on forever, the myths are many and well entrenched and folks are going to convince themselves they are doing the right thing even when the facts show different. Folks just don't seem to want to accept the fact that higher octane does not mean a more powerful gasoline, octane is NOT a measure of how powerful a fuel is!


Also the alcohol thing keeps popping up but everything I am saying about regular vs premium assumes the same alcohol content for both. There is absolutely no doubt that gas with alcohol in it will get less mileage than 100% gasoline, the more alcohol in the fuel the less the mileage the driver will get and that's one well known belief that certainly is true!

[10x]

There might be Laws governing the quality of what is sold at the pumps but so long as the taxes are paid quality of product takes a back seat in Canada.
I don't believe there is any requirement to meet a specific standard. Discount service station chains sometimes buy the dregs (salvage fuel) from tank farms, blend it all and then sell it at 87 Octane. I fondly remember "Turbo, the pumper people" selling gas that got less than 50% of the mileage of regular gas from brand name service stations,
In my '76 Chev 3/4 ton with L series 350 - 27 imperial gallons of fuel would take me just over 200 miles when purchased from Turbo, 12 gallons from Gulf or Shell would drive the same vehicle over 310 miles and leave 4 gallons in the tank. Sometimes saving $0.10 a gallon costs you more on the highway.

[Petrol & Powder]

oldred--
The Passat may require premium fuel, but not at the altitude where we live. Compression ratios are degraded the higher up in altitude you go, unless you have a turbocharged engine, which my daughter does not. You lose about 3% performance in an unturbocharged engine per thousand feet, so we lose 15-20% horsepower up here. I would suspect C/R is lost at about the same rate, so instead of, say 9.5 to 1 ratio, it drops to 7.5 - 8.0 to 1. Our regular is only 85 octane.
Not to split hairs but higher altitude (lower atmospheric pressure) does not technically change the compression ratio but in a naturally aspirated engine (no turbo/supercharger) it does reduce the initial amount of air/fuel mixture being compressed. Therefore, greater altitude does reduce the engine output because there is less air/fuel being compressed but the actual compression ratio is the same. The end result of reduced power is as you describe but the method that causes that reduction in power is due to starting with less air to compress.
Admittedly a fine point because the end result is the same. You can get by with lower octane rating at higher altitude because the compressed air/fuel mixture is less dense to start with, therefore at a lower peak pressure when ignited.

[MaryB]

40 mile round trip for av gas... marina??? I live on the prairie! Pretty much stuck with what the co-op carries for fuel


Go to your local small airport and buy some 100LL (100 low lead or avgas) and run it in your small engines before storage. It will last all winter or summer without going bad and gumming up your carbs. Or check at most marinas for ethanol free gasoline. These fuels cost more, avgas is $4.65 per gallon at my airport in Michigan, but its well worth it for avoiding the problems of ethanol blend fuel. One other thing, if you get some 100LL, do NOT put it in anything with a catalytic converter.

[Lloyd Smale]

that comes for old school thinking. Back in the 50s and 60s premium had additives to clean your fuel system that regular didn't. Octane is a burn suppressant. It slows combustion. Nothing more. It retards burning to prevent pre ignition (spark knock) which can destroy a motor. Yes some newer cars will perform better with premium. they do it because there computers will keep advancing timing until they sense spark knock and premium will allow more advance and increasing advance is basically increasing static compresson which creates horse power. More hp and you motor doesn't have to work as hard to push your vehicle down the road and that may increase gas mileage. thing is 95 percent of the vehicles on the road have a computer program wrote for regular fuel and the small increases you get will never make up for the cost of the fuel. Now this can change if you have access to someone knowlegable enough to reprogram your computer to make the most out of that premium fuel.

what is definitely true is ANY no computer controlled motor that was designed for regular fuel (compression rations and timing set for regular) will ALLWAYS perform better using regular then they would using premium. Even most of the older computer controlled vehicles will because there computers weren't advanced enough to take advantage of the change in octane.

Now alcohol. Alcohol is a burn retardant when compared to gasoline. If you take E85 and compare it to premium gas with no alcohol that is 93 octane the E85 will actually allow more timing and compression then the 93 will. If you take for example my new 2015 sliverado. It is flex fuel rated and has a program in the computer that senses the use of E85 and ajusts for it. What it does is put a lot more advance in the timing and more fuel pressure to make up for the low energy rating of the fuel. What does this do. Well It adds 20-30 horse power to the truck instantly and decreases fuel economy by 20 percent. Its not a bad deal for someone who occasionaly pulls a heavy load. On those trips run E85 and take advantage of the HP increase and being the motor isn't going to have to work as hard to make power you might even see somewhat of a gas millage equalization.

What stinks I guys wanting fuel for there weed wacker, lawn mower, chain saw ect that absolutely don't want alcohol in there fuel are stuck with premium fuel that is harder to ignite and make there tools harder to start and not run as strong.
I understand the relationship between compression ratios and octane ratings but I seldom try to explain it. I once heard a trusted indy mechanic wax eloquent about "treating" a car with premium from time to time to keep it performing like it should. Yes, my air-cooled engines prefer higher octane fuel but the 4.6's under my carport are quite happy with 86 or 87 octane fuel, one will even burn E-85 if I could find it.

[Lloyd Smale]

what altitude does plane and simple is reduce the oxygen level in your fuel air mixture richening the mix to the point that it doesn't have enough oxygen to burn properly. the way to compensate for this is to add more air (forced induction) or take out fuel to get the mixture back to the point it burns properly which will result in less fuel air mixture burned and less power.

The difference in your arguments are the difference in mechanical compression and static compression. Mechanical is fixed reading taken a set level of oxygen at a set place in the stroke of a motor.. Static compression is true compresson. It can vary by fuel air mixtures, timing, mechanical compression ratios and induction pressures. An example would be a turbo motor. Mechanical compression set at about 8.5-1 which is where a lot of turbo motors are set. True static compression under boost can be as high as 14-1.

This is why most turbo motors have computers that retard timing drastical with boost increases and even run alcohol injection on higher levels of boost. Bottom line is a turbo motor that doenst increase boost pressures at high altitude is going to loose power just like a naturaly aspirated motor. Thing is most turbo motors have computers that sense at altitude that the fuel air mixture is getting rich and tell the waste gate to open a bit more and produce a bit more boost to make up for it and yes that does increase static compression. Where turbo and blown motors really make more power is with there lower mechanical compression ratios come larger combustion chambers that allow more fuel and air to come and burn with the same static compression of a naturaly aspirated motor that needs to compress its fuel air mixture mechanicaly, in which in a this increases there displacement in comparison to a motor that is naturaly aspirated with the same specs.
Not to split hairs but higher altitude (lower atmospheric pressure) does not technically change the compression ratio but in a naturally aspirated engine (no turbo/supercharger) it does reduce the initial amount of air/fuel mixture being compressed. Therefore, greater altitude does reduce the engine output because there is less air/fuel being compressed but the actual compression ratio is the same. The end result of reduced power is as you describe but the method that causes that reduction in power is due to starting with less air to compress.
Admittedly a fine point because the end result is the same. You can get by with lower octane rating at higher altitude because the compressed air/fuel mixture is less dense to start with, therefore at a lower peak pressure when ignited.

[oldred]

Yes some newer cars will perform better with premium. they do it because there computers will keep advancing timing until they sense spark knock and premium will allow more advance and increasing advance is basically increasing static compresson which creates horse power.

Not exactly, these engines set timing at an optimum for the conditions determined by several inputs, air flow, air temperature, throttle position, etc but for the vast majority of the time the timing will be exactly the same regardless of fuel grade (with the exception of a sub par fuel that would knock/ping constantly), just cruising down the interstate for instance the timing (and mixture on those that also include this compensation) will be the same for either gasoline. When conditions are encountered that lead to pinging the computer will then compensate but revert back when knocking conditions are no longer present. The idea that the computer is advancing timing until knocking occurs in all driving conditions would be extremely problematic, in low load cruise conditions the optimum max timing would be surpassed long before knocking is encountered, there's more to timing than just spark knock! Timing set to far advanced in cruise, idle and other low load conditions can result in driving issues and economy losses other than just knock/ping and the optimum economy settings for these engine systems will be the same with either fuel in all but high load knock inducing situations.


The purpose of the system was to be able to take advantage of slightly higher compression, ignition and fuel curves of higher performance engines without requiring the use of high octane fuel all the time even when it's simply not needed as was done in the past. They do this by designing an engine that would otherwise require high octane fuel under heavy load but then include the ability to compensate mechanically instead of simply buying a more expensive fuel that would be required for only brief driving conditions. Even a very high compression engine, 12 to one even, would run on regular in low load light throttle conditions BUT it wouldn't be practical because the engine would then beat itself to death during acceleration or other loading conditions, and indeed this same system is used on modern high performance engines that without the system would require a higher octane gasoline than is even available today.

[Petrol & Powder]

Well, we wandered pretty far off from the OP's thrown rod :-) but yes, I understand the difference between mechanical & static compression. And I understand how boast pressure, adjustable timing, differences in altitude and the amount of available oxygen and octane ratings all effect available power. Of course none of that helps the OP with what's left of the rod hanging out of the bottom of his oil pan....Nor is any of that relevant to why that catastrophic failure occurred.

Now, to return to the octane discussion briefly. There are a lot of people that have convinced themselves that premium gas is better because it produces more power, is better for the engine, runs smoother,..... makes them taller, better looking, smarter and more enlightened. ;-) They had a little help from the fuel companies and slick marketing but they didn't require much help to feel enlightened.
Unless you have an engine that is capable of utilizing that higher octane rating to produce more power; you are wasting your money by purchasing that more expensive fuel.

Some engines do have the ability to utilize higher octane fuel (higher compression ratio) and produce more power from a given displacement but most people are just throwing money away because they think they know something.

[oldred]

Some engines do have the ability to utilize higher octane fuel (higher compression ratio) and produce more power from a given displacement but most people are just throwing money away because they think they know something.


And these engines are so marked in the owners manual and usually at the filler cap and sometimes on the fuel gauge. Lot's of misunderstandings about this and conflicting articles on the internet have made the problem worse. Yes some engines do definitely have the ability to make more power with higher octane fuels otherwise the high octane would not be needed at all but this is where the confusion comes in for a lot of folks, the higher octane simply ALLOWS the engine to be built to a higher performance spec rather than the fuel itself making more power, if that higher performance is not designed into the engine though compression ratio and valve/ignition curves the engine quite simply does not have the ability to reach the power levels where higher octane would advantageous and nothing would be gained (except a lighter wallet!). In these high performance engines a low octane would cause problems even with computer compensation, "pre-ignition" is the mixture firing before the spark even occurs so there can be a lot more to the premium/regular fuel situation than just timing.

The above mentioned idea that the computer seeks out the higher octane fuel by adjusting timing until knock is encountered is an all too common misunderstanding, it does in some situations such as the knock inducing high load conditions but if this were done during all driving conditions it would result in less power/economy rather than more. Adjusting the timing up to the detonation point in lightly loaded driving conditions would result in timing that would be much too far advanced for either fuel.

[Lloyd Smale]

might be with some or even most cars today but not all. Like I posted my 2015 chev will respond about instantly to and increase timing and fuel pressure when it senses E85 or it senses premium gasoline. If it didn't then flex fuel wouldn't work and either would turbo motors that have to run both under boost and not boosted. Youd be strapped by the fuel/timing curves of the poorest grade fuel cruising down road with flex fuel and stuck with the retarded timing and richened mixture of a turbo at boost cruising down the road and that just isn't the case. With the modern computer and direct injection technology keeping the tune just short of detonation is possible. Its also why we can run compression ratios in todays motors at levels on regular gas that would have lasted buy hours on premium fuel 20 years ago.
Not exactly, these engines set timing at an optimum for the conditions determined by several inputs, air flow, air temperature, throttle position, etc but for the vast majority of the time the timing will be exactly the same regardless of fuel grade (with the exception of a sub par fuel that would knock/ping constantly), just cruising down the interstate for instance the timing (and mixture on those that also include this compensation) will be the same for either gasoline. When conditions are encountered that lead to pinging the computer will then compensate but revert back when knocking conditions are no longer present. The idea that the computer is advancing timing until knocking occurs in all driving conditions would be extremely problematic, in low load cruise conditions the optimum max timing would be surpassed long before knocking is encountered, there's more to timing than just spark knock! Timing set to far advanced in cruise, idle and other low load conditions can result in driving issues and economy losses other than just knock/ping and the optimum economy settings for these engine systems will be the same with either fuel in all but high load knock inducing situations.


The purpose of the system was to be able to take advantage of slightly higher compression, ignition and fuel curves of higher performance engines without requiring the high octane fuel all the time even when it's simply not needed as was done in the past. They do this by designing an engine that would otherwise require high octane fuel under heavy load but then include the ability to compensate mechanically instead of simply buying a more expensive fuel that would be required for only brief driving conditions. Even a very high compression engine, 12 to one even, would run on regular in low load light throttle conditions BUT it wouldn't be practical because the engine would then beat itself to death during acceleration or other loading conditions, and indeed this same system is used on modern high performance engines that without the system would require a higher octane gasoline than is even available today.

[oldred]

With a flex fuel engine switching between E85 and "real" gasoline it would be true in a sense but that's a classic case of comparing apples and oranges, we have been discussing premium vs regular grades assuming the same alcohol content in each, with true gasoline there is no difference in BTU content between grades. With true gasoline most driving conditions are going to be the same regardless of fuel octane but alcohol has a MUCH higher octane rating and a much lower BTU content (power per pound) so when switching between gasoline and alcohol rich fuels in a flx fuel system a lot more happens than just timing adjustments. When these gas-only vehicles equipped with a compensation system are running high octane vs regular grades compensation is going to be the same except for brief periods of knock inducing high loading conditions.

BTW, E85 has an octane rating of around 100 or 105 which is much higher than any premium 100% or low ratio mix but power and fuel economy for E85 is notoriously low. This is not surprising to folks who know that octane does not equate to power since the BTU content is so low in alcohol that it simply takes a lot more fuel to the engine in order to make the same power vs 100% or lower ratio mixes. If the E85 were cheaper than "normal" gasolines by enough to offset the reduced fuel mileage it might be a good idea but so far that's rarely the case and is the reason E85 never lived up to it's expectations. Still if another major gas crunch occurs, and that's always a real possibility for whatever the reasons, folks with the flex fuel vehicles may be very happy indeed!

[oldred]

and neither would turbo motors that have to run both under boost and not boosted. You'd be strapped by the fuel/timing curves of the poorest grade fuel cruising down road with flex fuel and stuck with the retarded timing and richened mixture of a turbo at boost cruising down the road and that just isn't the case.

Of course those engines can benefit from higher octane and no one is saying they won't but haven't you noticed that some of us have been clearly saying that all along? Those are examples of engines that are DESIGNED for higher octane fuels, obviously turbocharged and supercharged engines are high performance examples! This whole discussion is about the myth, and it is a myth, that premium fuels give better performance in engines meant, and so labeled, for regular grades of fuel. That's the whole point, unless an engine is of a turbo/supercharged or other high performance design (the vast majority of vehicles are not) then there simply is no reason to waste money on premium fuels. Still the myth is widespread that buying premium is still a better choice despite the vehicle being labeled for regular grades, THAT is the point not that premium would be a waste in engines designed for it because obviously it wouldn't. That misunderstood computer compensation system is often used to support this reasoning that premium is better even though the engine is designed to run on regular.

[Lloyd Smale]

I wouldn't never argue that premium is a better fuel for a motor designed to run regular. For the most part your car will run worse especially if your already dealing with older plugs, wires ect. Its just harder to ignite period. We used to chuckle at the idots on cold nights with there snowmobiles parked outside the bar. Now we ran high compression motors that needed but stock snowmobiles don't have enough compression to warrant it and there were allways guys out there when it got below zero cranking and cranking on there sleds because they couldn't get that high octane fuel to light off in the cold. Just take your weed wacker that running great on regular and put some premium in it and youll notice right away it doesn't start as well. Problem is with all of these toys is to most of them alcohol is poison and its tough to find regular without alcohol anywhere. So you buy premium so you don't ruin your **** and crank and crank.
Of course those engines can benefit from higher octane and no one is saying they won't but haven't you noticed that some of us have been clearly saying that all along? Those are examples of engines that are DESIGNED for higher octane fuels, obviously turbocharged and supercharged engines are high performance examples! This whole discussion is about the myth, and it is a myth, that premium fuels give better performance in engines meant, and so labeled, for regular grades of fuel. That's the whole point, unless an engine is of a turbo/supercharged or other high performance design (the vast majority of vehicles are not) then there simply is no reason to waste money on premium fuels. Still the myth is widespread that buying premium is still a better choice despite the vehicle being labeled for regular grades, THAT is the point not that premium would be a waste in engines designed for it because obviously it wouldn't. That misunderstood computer compensation system is often used to support this reasoning that premium is better even though the engine is designed to run on regular.

[oldred]

Back in '69 I bought a new Shelby Mustang GT500 with a 428 "Super CJ" (Basically a stock police interceptor engine) but I immediately made some major modifications, camshaft, 427 med. riser heads and intake with duel 4 barrel Hollys and pistons to match those 427 chambers at 12 1/2 to one compression. The highest octane gas we could get was Sunnoco 260 and Gulf No-Nox (how's that for nostalgia and how may remember those?). It ran fine on either but the darn thing was a bear to start, it cranked over just fine with the duel battery setup in the trunk but it would crank forever before it finally lit. Later I discovered that several other brands of gas that were just a point or two lower in octane number would also run without knock and it fire right off the bat as soon as it started cranking!

[Lloyd Smale]

yup I do remember 260 sunnoco. It even made your exhaust smell cool. I also remember a few buddys who used it with some serious motors with a lot of compression that used to use a squirt bottle to spray some regular right in the carb to get there motors cranked. Drag racers often did the same. I kind of chuckle with the gas milage complaints with e85. Heck you can use E85 in something like my old grand national, tune for it and crank the boost up to about 25psi and put down an easy 400 rear wheel hp with no trouble at all and still get 16-18mpg. Look back in the 70s when something like a ls6 chevelle that was one of the quickest of its time and it probably put down 350 to the rear wheels with a perfect tune and got 10 mpg on a good day with a tail wind.

[popper]

Several chevy 70-80's motors had poorly designed oil drain, when overheated/dirty they clogged. I put drains in the valve covers to avoid spilling a coupe quarts from each when cleaning the drain holes. MIL's old ford parrafined so bad I couldn't add oil till I cleaned the filler hole.

[skeettx]

OK osteodoc08, please give us an update
Been a while
Thanks
Mike

[osteodoc08]

Still waiting on long block from GM and they won't start a tear down until new motor at dealer. Hoping to have it in early next week and if everything goes well up and running late this week or early next. I plan on running by and snapping pictures if allowed and I have time.

ive been following the other debates. Entertaining to say the least.

[rockrat]

Oldred--So, still have your GT500??? Pics if you do!!!

Osteodoc08---hope this one lasts alot longer!!

[Lloyd Smale]

problem isn't rare. That motor that switches from 8 to 4 cyl has been a headache from the start for them. When it switches to 4 cyl all the oil that quenching the piston on the deactivated cylinders gets sucked into the pvc system and burned in the live cylinders. It carbons up the live ones real bad and causes trouble. they supposedly corrected this in 2014 but from what ive heard it just isn't so. My new 2015 will be reprogramed to eliminate this switch off cylinders. From what ive gleamed it only saves if you do a lot of freeway driving and most rural drives will actually cause you to use more fuel. Its done strictly so that under controlled circumstances they can show the epa better mileage. Gm is not allowed to turn the off because of the epa and will void your warrantee if you have a crappy dealership. So you need a controller or range unit to be able to put it back on when you go in for service. These ls based motors are about bullet proof other then this wart on them.

[oldred]

Oldred--So, still have your GT500??? Pics if you do!!!

Osteodoc08---hope this one lasts alot longer!!


No it was stolen back in '76, caught the thieves but the car had been cut up for parts. Seems the Shelby fiberglass body parts were bringing big prices and there was a ready market in those days to turn a '69 or '70 Mustang into a Shelby look-alike. When they were caught all I managed to recover was the seats and those were identical to any other Mustang Mach One.

[TXGunNut]

Still waiting on long block from GM and they won't start a tear down until new motor at dealer. Hoping to have it in early next week and if everything goes well up and running late this week or early next. I plan on running by and snapping pictures if allowed and I have time.

ive been following the other debates. Entertaining to say the least.

No engine yet? In the past I've shipped engines all over the country and had them shipped from Memphis and Michigan over the past several weeks and they're sitting in the shop within 3-4 days. Guess it could be on backorder. Might want to drop by the shop tomorrow, I'm betting there's a big brown box sitting there waiting for a mechanic to get a round tuit.

[osteodoc08]

No engine yet? In the past I've shipped engines all over the country and had them shipped from Memphis and Michigan over the past several weeks and they're sitting in the shop within 3-4 days. Guess it could be on backorder. Might want to drop by the shop tomorrow, I'm betting there's a big brown box sitting there waiting for a mechanic to get a round tuit.

Perhaps. My service writer and I have a good relationship. I even have him some 22 ammo when it was super scarce so he and his boys could shoot. They've always done me right on things and don't expect that to change. He keeps me updated on things and is always on top of things.

[MT Gianni]

problem isn't rare. That motor that switches from 8 to 4 cyl has been a headache from the start for them. When it switches to 4 cyl all the oil that quenching the piston on the deactivated cylinders gets sucked into the pvc system and burned in the live cylinders. It carbons up the live ones real bad and causes trouble. they supposedly corrected this in 2014 but from what ive heard it just isn't so. My new 2015 will be reprogramed to eliminate this switch off cylinders. From what ive gleamed it only saves if you do a lot of freeway driving and most rural drives will actually cause you to use more fuel. Its done strictly so that under controlled circumstances they can show the epa better mileage. Gm is not allowed to turn the off because of the epa and will void your warrantee if you have a crappy dealership. So you need a controller or range unit to be able to put it back on when you go in for service. These ls based motors are about bullet proof other then this wart on them.
My 08 Dodge switches from 3-8 cylinders firing and has no trouble with burning oil or fouling plugs. Your mileage may vary.

[GREENCOUNTYPETE]

I know a guy who used to be an inspector on the GM line he failed several times the number of engines failed on any other shift after a while management noticed this wondered why he had failed so many he said because they had something wrong and pointed out what on each one , they had him come in early one day and he inspected the other guys engines and found several of the ones he should have failed , that is when they realized if all these engines were passing that should have failed and it had been like that for years and the failures after the sale weren't any higher they didn't need inspectors at that point and he was moved to a different part of the line. that is the way he tells it any way, I have no reason to believe he didn't do accurate work he seems to in everything else.

[osteodoc08]

Motor came in today. Will start tear down and replacement and should be up
and running by Thursday/Friday. I'll know more about what blew once the blown motor is out. Knock on wood, but no hassles from GM thus far. My only complaint is the interior of my F-250 is being trashed by the kids and wife. Crumbs, make up, power cords, diapers, wipes, etc.....She says she wants my truck now and doesn't trust her Yukon. I'm not so sure were gonna trade just yet.

[skeettx]

Give her WHATEVER she wants, you will be very happy you did !!!!!

[TXGunNut]

Good to hear things are moving forward. Yukon's a nice ride, I wouldn't fight too hard to get the F250 back. If you do, tho, I suspect a nice detail job will have her back in her Tahoe again.

[osteodoc08]

New motor is in. GM dealer is saying water in the tank was the culprit. I've heard of it causing poor running, but to grenade a motor?! It's not like it was submerged and hydro locked. I could see a bent rod from that, but water in the fuel? I told him that I wasn't about to shell out the money for a new motor if GM denies the claim. They'd have to work through my insurance or the last station I got gas or the bank could come pick up the car. I'm not about to shell out $10k for a new motor.

[jmort]

"GM dealer is saying water in the tank was the culprit."

That sounds bogus

"...or the bank could come pick up the car."

I did that long ago with with GMAC. I was so mad about the transmission in my Z 28, I told GMAC where the car was parked and to take it and shove it. They towed it and sold it at auction. Settled with them later for $2500.00. Better than paying for the balance and a new transmission. Didn't help my credit, but I was so mad I absolutely did not care. Now that I think about it I had another GMAC car that I bought new and engine died at 98K. Always used synthetic oil and changed it regularly. Traded it in on the Z 28. So one *** to another. Have not bought a new GMAC since.

[KAF]

Dex-cool leak into the crankcase, leaked at the intake manifold.

[BrentD]

FWIW, I had the engine on my F150 "hydro lock" when somehow fuel did not burn or pass out of one of the cylinders. It was at 96K and a new engine was installed, a loaner truck was made available and everything taken care of under warranty. There is not much doubt that my next truck will be a Ford also, and this is just one of several big reasons why.

[oldred]

New motor is in. GM dealer is saying water in the tank was the culprit.


That's 100% USDA certified BS!!!!! You have it pretty much nailed down as to what water can cause, poor running, miss-firing and even stalling out but to cause a thrown rod????? Ask them to explain in detail just exactly how that can occur and make it plain you WILL take them to court over it, I seriously doubt they would be willing to argue their BS explanation before an impartial expert in court of how this would be possible! I think this is just a low life attempt at hoping you will not know any better and just pay-up but when they see they are going to have to defend that bogus nonsense they will most likely suddenly have a change of heart and be willing to "help you out", just out of their own generosity and regard for their customers you understand! :roll:

[osteodoc08]

FWIW, I had the engine on my F150 "hydro lock" when somehow fuel did not burn or pass out of one of the cylinders. It was at 96K and a new engine was installed, a loaner truck was made available and everything taken care of under warranty. There is not much doubt that my next truck will be a Ford also, and this is just one of several big reasons why.

They had a bad batch of injectors getting stuck flooding the engine with fuel. Happened to my brothers who's was a 05 with the 5.4L.

[osteodoc08]

And the wife also left the gas cap off after getting gas and was driving home while it was pouring down rain the day before the happened. ***. She didn't realize she forgot to put the cap back on. So likely was water in gas tank but dang. A blown engine?! Ugh. We shall see what happens.

[oldred]

There simply is no way water in the gas tank is going to cause a thrown rod! If there was enough water in the fuel to hydro lock the engine then obviously it's going to stall and besides any water the injectors could pass into the cylinder with a fuel charge is only going to be a tiny amount of spray with the fuel and even that will be exhausted with each cycle, the only way enough water could accumulate in the cylinder to "lock" the engine would be if it were somehow streaming in fast enough and that simply can't happen! The more I think about this the dumber it sounds, I would love to hear the "mechanic" try and explain just how this could happen! Ask that idiot (yep I said IDIOT!) to explain in detail the sequence of events that would cause a rod failure from water contamination of the fuel, that should be quite interesting.

[BrentD]

They had a bad batch of injectors getting stuck flooding the engine with fuel. Happened to my brothers who's was a 05 with the 5.4L.
Indeed, that is exactly right. Mine is an 05 with the 5.4l Great truck otherwise.

[oldred]

A bad injector could indeed flood an engine with FUEL and cause it to hydro-lock but of course it would not matter if it was fuel or water in a case like that and if there was that much water in the fuel the engine would have stalled out. The description of what happened to this engine does not fit with a hydro-lock situation anyway, even then if the engine had of blown because a bad injector had allowed it to hydro-lock it would STILL be a valid warranty claim!


Also back in the days of leaded gasoline and carburetors it was not uncommon for engines to develop a "carbon knock" as we called it, so much carbon would build up in the combustion chamber and on top of the piston it would cause detonation and "dieseling" where the engine would continue to run (sort of anyway) after the ignition was shut off. A very common solution to this was to spray water from a water hose directly into the carburetor, a heavy spray NOT a steady stream, as this would cause the carbon to break loose and be both burned and blown out the tail pipe. The process would involve the engine ingesting far more water in a much shorter period of time than it would be possible for an injector to introduce into a cylinder and common as this was I have never heard of it hurting anything. Although I never did this I have seen on more than one occasion someone slowly pour water directly out of a container into the carburetor and this apparently never done any harm either! Unless a huge amount of fluid is introduced into the cylinder in one big "gulp" the exhaust stroke will limit the amount of fluid that will be contained in a cylinder at any one time.

[osteodoc08]

Wife went by to get something out of the Yukon. New motor is installed in vehicle and they have cleaned out the fuel system. They are going through it and allowing some run time to check for issues. After 2 weeks, I'll be happy to have it back. Wife wants to swap vehicles now. She doesn't "trust it". I guess next stop is body shop to fix the 2 minor fender benders she has been in so I'm not driving around a banged up vehicle.

[MaryB]

There is no way leaving a gas cap off is going to let enough water into the gas tank to even begin to cause an issue! Small amount of water in the fuel will do nothing, in fact I remember water injection kits sold to improve gas mileage back in the 80's. Had a spacer plate under the carb with a spray bar that put a small amount of water into the fuel mix. Someone is blowing smoke up...

[Lloyd Smale]

got to agree with others. About the only way to hydrolock an engine is to drive it into a lake so deap that the intake sucks water. I would demand the phone number for there customer service. (theres a different one then the one that's listed) I would tell them either they fix it or your contacting your lawyer and it wouldn't even hurt to have a lawyer draft a letter to send them. A couple hundred bucks for a lawyer to write a letter is cheap compared to the bill your going to get. First though nicely tell the service manager that your not buying the hydrolock **** and tell him you will give him a chance to take care of this before you go over his head.

[osteodoc08]

The vehicle is fixed and should be ready today. GM has covered the motor and there is no evidence for that to change. I'm only being charged to dump the tank, and clean the fuel lines and injectors, which is reasonable given the amount of water in the tank. I spoke with my typical service writer this morning and he's not really sure why the motor grenaded. He's been out sick a few days and so I had dealt with another service writer and that's what he told me because he "Didn't know me from Adam and just read off the repair sheet". Jason, the one who typically takes care of me and who I have the 22 ammo to in the past, has taken care of me and given me no real pushback from GM so I am thankful for that. I'll have to bring him a small box of CCI I've got sittig on the shelf as a thank you. So all things considered I really can't complain. I have the remainder of the 5yr/100k mile warranty to see if this one explodes too. I'm hoping I got a good one this to around and will be a little more diligent about saving receipts. I'm sure I'll never truly find out why this motor grenaded but I've got a new one in the engine bay and can't really complain.

[oldred]

As long as they are footing the bill for the engine it doesn't matter if they blame it on Gremlins! As far as having water in the tank most vehicles with any time at all on them will have at least a small amount of water in the bottom of the tank, it's almost normal due to condensation and the fact that a lot of the fuel we buy will be contaminated. Usually this will be a dark dirty looking mixture that appears more like a jelly-like mass than clear water so having it removed and the tank/lines flushed out is probably not a bad idea at all.

[Plate plinker]

Curious as to how much water was in the tank if any.

i dropped the tank on my explorer last winter and could not find any water matter of fact it was rather clean in there.

[osteodoc08]

I was told they siphoned about a soda bottle worth and there was 2" of water. Yes, I realize a soda bottle is an "unapproved container", but that's what I was told.

[oldred]

A small amount of water in a fuel tank usually doesn't hurt much of anything and is quite common mostly due to condensation, there is a lot of truth to the old saw about keeping the tank full keeps water out of it. The problem starts when a large amount of water is introduced into the tank, usually from a contaminated fuel source and the pump sucks more water than gas. This can of course cause stalling but it can, and will, cause other problems such as clogged fuel filters and injector damage but the engine will simply stall out and quit running before enough water could enter into the combustion chambers to cause serious mechanical problems. Water from condensation forms very slowly and when it reaches a level where the fuel pump starts to pick it up with the fuel it gets sent to the engine and exhausted out the tail pipe so the level reaches a point of balance and rarely gets bad enough to even be noticeable never mind causing engine damage. The reason it can be pumped to the engine without causing noticeable problems under normal circumstances is that we are talking about a tiny amount, a few drops at the most, entering the fuel system at any one time and water from condensation in the tank is also only a very small amount usually forming over a long period of time.

Over the years I have removed manyl fuel tanks for various reasons ranging from damage to leaks to replacing fuel pumps and/or fuel gauge sending units but by far the biggest reason was fuel pump replacement, between 2000 and about 2005 Chevy trucks were so prone to this problem that we kept a new pump/unit on hand as a normal stock item. Of all the tanks I have removed or seen removed I would estimate that 75% or more had at least some water in them usually mixed with other contaminates. Rarely did any of these vehicles exhibit any problems from this contamination but then again it must be considered we are talking only a few ounces at most. One vehicle I did have water causing problems with turned out to be one of my own, it was my '93 Ranger 2.3 4 cyl that we use here on the farm and it often gets fueled from a 55 gal drum. What happened was that it started clogging fuel filters, it would start mis-firing under heavy load (starving for fuel) and changing the fuel filter would seem to solve the problem for a while but after changing four filters over a period of several weeks I pulled the bed off the frame and removed the tank for cleaning. It had close to half a gallon of water in it and even the foot strainer on the bottom of the pump was starting to clog from a gooey-like substance but simply flushing the tank and changing the filter once more solved the problem permanently, the only real damage was ruining the fuel filters.

[Lloyd Smale]

that much water and id be nervous someone didn't put it in there intentionaly. Id be thinking locking gas cap if I were you. that is if the dealer is being straight with you.
I was told they siphoned about a soda bottle worth and there was 2" of water. Yes, I realize a soda bottle is an "unapproved container", but that's what I was told.

[osteodoc08]

that much water and id be nervous someone didn't put it in there intentionaly. Id be thinking locking gas cap if I were you. that is if the dealer is being straight with you.

I have no reason to think otherwise. Of course if they siphoned from the bottom, more water will be sucked up so the amount may not be representative other than proving there was water in the tank.

Ive been purchasing here for almost a decade and dealing with the same folks. I've bought 4 new vehicles from them during that time frame and have let them do all my general repairs be it warranty or not. When I'm short on time or if not able to due to time, they've done my routine maintenance. They're good folks and in a small town, reputation can be destroyed very quickly and can destroy a business very quickly with unscrupulous activity.

My wife also admits to leaving the gas cap and gas filler door open while it was pouring down rain.....it was a frog strangler. I don't have any enemies that would sabotage me. So I suppose the water was from the rain.

[osteodoc08]

Just got a call. GM covered motor. I cover fuel system flush and clean. Vehicle is done. Yay!

When asked what caused the damage, I was told that the motor is sent back to GM and they're guessing some internal issue. Either way. New motor. I'll be happy to have it back.

[jmort]

Good to see a conclusion that seems fair enough.

[oldred]

Fair enough and the fuel system flush was a good idea regardless. Two inches of water in a soda bottle is not much at all and if they siphoned from the very bottom of the tank it's likely that what they saw there was the most of it, in any case a pint or more can be in the very bottom without being sucked into the system or at least at that amount only a very few drops at a time. If you run a vehicle out of gas there is usually at least a half gallon or more, most likely more in most tanks, of fuel (or whatever!) left in the bottom, this unusable fuel prevents small amounts of accumulated water and other debris that settles to the bottom from being picked up and clogging the filter/injectors. I think most folks might be surprised at what is lurking at the very bottom of their fuel tanks if the vehicle has any substantial time and/or miles on it!

[MaryB]

I had a used van I picked up. Someone had used an orange rubber garden hose to siphon and when it got stuck they shoved it in the tank. I had dropped a rebuilt motor in it and the fuel filters kept plugging with this weird orange stuff. When we dropped the tank most of the hose had disintegrated into particles and was being picked up into the intake because it mixed and suspended in the gas while driving. Flushed the tank and fuel lines, put it all back together with a new fuel pump and filter and it was good to go. I put 100k miles in it and had invested $1,200 total.

[Lloyd Smale]

I wasn't referring to the dealer doing it but vandals.

[osteodoc08]

I wasn't referring to the dealer doing it but vandals.

I understand. Unless my wife PO somebody, it wouldn't be me that's the target.

Got it back. She's running good. Total damage less than 3 bills for a new motor, co deductible and fuel clean/flushed. Can't complain.

Now to get body work done.

[osteodoc08]

Notes said "cylinder #7 rod through block" and gave an authorization number for new motor. The old motor was already crated up and shipped back. I was hoping to get a few photos

[snowwolfe]

Glad to see a happy ending to a serious issue.
I would just like to add my opinion to running a supercharger engine at high altitude as I live at 7,000 feet. You can force all the air into the motor you want but you are still going to lose 3% of the horse power for every 1,000 feet you go up.
This is one of the prime reasons a speed shop always gives a corrected dyno number for sea level when they dyno a car.
"thin" air is still thin air whether or not it is forced or sucked into the motor