ATF in engine oil

[Jonesy]

Long story short, I've got a 1996 Saturn with 260,000 miles on it. I cracked open the valve cover around 250,000 miles and it was surprisingly clean. I've been thinking about adding some type of detergent to the oil to help remove any deposits in the lower end that may be lurking. I haven't cracked the bottom end at all so I really don't know what may be lurking in there.
My friends and family swear by adding ATF in just before an oil change, but with such high mileage I'm not sure what to expect. I don't want to dislodge a big chunk and send it into the bowels of the engine. Anyone ever tried it on something with high mileage?
I'm not sure I really want to add anything at all, any advice would be appreciated. The car runs like a champ as is so I may just leave well enough alone.

[waksupi]

Techron gas treatment cleaned my engine better than anything else I tried, and increased my mileage by a good bit.

[garym1a2]

If its clean at 260k why change your routine?

[DLCTEX]

Gary beat me to it. Don't argue with success!

[SeabeeMan]

The dislodging a chunk is the same reason I've always avoided (and been told to avoid) transmission flushes. I would just keep going they way you have been.

On a side note, we added lots of ATF to JP-5 in the HMMWV's back in the day when we ran convoy escort. The JP-5 had no lubrication and we would go through multiple fuels pumps a week between the 6 gun trucks. Adding a good "glug" of ATF to the tank when fueling made it so we only had to switch one or two fuel pumps a week.

[GREENCOUNTYPETE]

a majority of motor oils now have detergent in them if they don't say NON-DETERGENT on the label chances are they have detergent and why your valve cover was surprisingly clean , I wouldn't mess with it

[Uncle Jimbo]

After you do this, the engine will start to burn oil at a rapid rate. The ATF will clean all the carbon from behind the rings and the rings will lose tension because they are worn. The carbon behind them acts like a spacer and helps keep the rings with tension and from collapsing.
But this is just my opinion.

[bob208]

engines gunk up from the top down. so if the top end is clean leave it alone. atf is made for transmissions not engines. if you change the oil and filter when they are suppose to be and don't use Quaker state you will be fine.

[too many things]

would not do to a gas engine but we add it to older diesel as the new **** don't have the lubes in it.

if its worked this long don't mess with it

[runfiverun]

well your getting close to the point I finally sent my 65 Newport to the scrap heap. [290-k]
I always poured a quart of atf in the oil a week or so before an oil change.
the engine still rang strong except for valves needing seats for the unleaded gas.
the rest of the car was pretty much falling apart around it.
I also done it to my 98 chev pick-up which I finally traded in at well over 200-k [and still miss]

I don't add atf in any of my new cars, the oil is thin enough for it to not be of help.

[bhn22]

At 250K, I wouldn't change anything now. Just continue on your oil change schedule as before and keep going as long as possible.

[Outpost75]

Much safer to add Lucas Oil top cylinder lubricant to your fuel. An over-dose will not hurt the engine, just smoke a bit. I add 2 oz. per ten gals of fuel to all my high mileage vehicles, both gas and diesel. Sea Foam is another good product, but keep ATF out of the engine if you plan on driving it over 200,000 miles.

[Jonesy]

I've sea foamed this baby when it hit 200,000 and man oh man, did some stuff come out that tailpipe. The only parts I've ever replaced are a starter motor, a few gaskets and hoses, and most recently an EGR valve. Other than that, she's complete as she was from the factory. I wasn't entirely sure where sludge begins, I assumed toward the bottom as gravity may have some effect on pulling it down to the oil pan.
It's the ugliest thing on the road, the paint is nearly fallen off the thing altogether, but it's the best car I've ever had. My wife had a '94 with well over 300,000 miles before we scrapped it. Can't beat those mid 90's Saturns when it comes to reliability. I think I'll take the easy route and leave it alone, just change the oil.
Thanks everyone!

[leadman]

I would not change anything at this point as it may cause you problems.

Rich, when I worked for the City Of Phoenix as a Shop Foreman the City Council decided JP5 would be a cleaner fuel for our diesels. No end to the fuel leak problem, especially in the Ford ambulances. We also added ATF to the fuel so the pumps would live awhile. This was before low sulphur diesel.

[fecmech]

engines gunk up from the top down. so if the top end is clean leave it alone.

A big +1

[Mytmousemalibu]

Unless it has been a problem child I would let'er be. You run the risk of causing more trouble than good! I've worked on cars all my life and the addage of, "If it ain't broke, don't fix it", is real sound advise!

Now if you bought the car used and it was gunked up to high heaven, that is another story. My 03' Chevy Crapalier was this way, I don't think anyone knew it had an oil filter. It started to make a nasty rattle which was the timing chain slapping the case because the chain tensioner was so cruddy it had stuck and let the chain go slack. A new tensioner and a regiment of short oil changes with a high detergent oil will help but adding anything that will really dissolve the crud risks plugging something up. I was a BMW master tech before I retired automotive work. BMW for a long time had a 15,000 mile oil service schedule which is way too much. On cars that were treated to this and followed the factory service to a tee, the engines were terribly sludged up inside. We were able to clean many up to a large degree with a short interval/high detergent oil service. Only engines that were close to the scrap heap did we try flushing them. We used 20w50 with about a quart of diesel fuel added to the oil as it dissolves deposits really well. This was only run this way at idle/parked and let get good and hot and run for a while longer, pulled back in the shop, changed the oil and filter again, drive a short while, check filter, drive more, change both again. Then sent home with a good high detergent non-syn oil and placed on a short interval service for a while. Saved quite a few folks from buying engines. My LB7 engine'd Duramax has pop'ed a few injectors before which it released diesel into the oil since they mount under the valve cover, that is the cleanest, most spotless engine inside that I have ever seen, let alone it being a diesel. It has 170,000mls on it.

[JonB_in_Glencoe]

I've sea foamed this baby when it hit 200,000 and man oh man, did some stuff come out that tailpipe.
...snip

I'd recommend Seafoam in the crankcase.
http://seafoamsales.com/using-in-crankcase-oil/

I assume you put seafoam into the upper engine via the vacuum system ? or directly into the fuel injection ?

A long time ago, Paul Brand, of Minnesota talk radio fame, KSTP 1500's "Auto talk" use to recommend the Seafoam tuneup(once a year?) 1/3 of a can into the gas tank, 1/3 of the can into the crankcase, and 1/3 of a can sucked into the upper engine via the vacuum system(or in the carb on a carb type fuel delivery system). Of course Seafoam was a sponsor of his show

[goodolejim]

DON"T DO IT !!! A few years ago I decided to give my Datsun which used no oil between oil changes a treat at 175000 mile. Switched to full synthetic oil. It started smoking to the point ten days later I pulled the engine for a rebuild. In case anyone missed the point , DONT MESS WITH SUCCESS!

[Jonesy]

Yeah Jon, I used 1/3 in the oil, gas, and vacuum line each. Smoked like hell but seriously improved idle and felt like it restored a bit of power. That junk really does work, at least in the piston side of things. Pulling a plug before and after you can really see the difference it makes on the piston's head surface. I threw it in through the PCV line just behind the intake slowly until the last bit where I threw the line into the fluid to stall the motor out. After it sat, I blew clouds around the entire neighborhood.

There's no look that you get from the neighbors quite like the one you get after seafoaming an old engine.

[Frank46]

Kinda reminds me of one old timer at work when he did an oil change. He'd dump the old oil and leave the old filter in place then fill the engine with Mobil DTE light which is a steam turbine oil and what we used in all of our steam and electric driven fuel oil pumps. After filling the engine with this oil (5 quarts) he'd start it up and let it sit until it got warm then shut it down. Then dumped the oil and filter. The amount of crud that came out was astounding. then he just put in a new filter and regular motor oil. Drove that car for years and still had it when he retired. Frank