A question for metalurgists regarding cooling system flushing

[tommag]

A friend has a mid 90s freightliner that has been run with no antifreeze and has a lot of rust in the coolant. He asked me about a flush, and I thought phosphoric acid would be a good idea. However, given the different metals in the system, (copper in the oil cooler) I'm wondering about galvanic corrosion.
Thanks in advance for your expertise.

[jonp]

Is there a reason he does not want to use one of the commercial flushes as in cost? I'm wondering why he would run a truck on straight water like that, too.

[tommag]

He just bought this truck, and is in the process of fixing it up. A store-bought flush would be fine. The question is aimed at getting the best results, rather than the least cost.

[Outpost75]

Use the commercial flush. Inspect the inside of the cooling system with a fiber-optic probe if possible. If you don't get the results you want the flush could be repeated. If not immediately, then simply at a shorter interval. Be sure to pressure and leak test. Older cooling system may need a sealant after flush if you cannot afford to replace it now. Good luck.

[NSB]

Commercial flush. It has acid neutralizers in it to prevent a lot of future problems from what ever was put in there before.

[bob208]

flush it with out the radiator hooked to the motor . the flush will break loss the rust in the block and clog up the radiator. learned that the hard way.

[Houndog]

I hate to be the bearer of bad news but if that Freightliner is powered by a Cummings or a Cat he will more than likely have to replace the cylinder liners very shortly! Pure water in the cooling system leads to air cavitation on the liners and they will pit through under the o rings on the liners extremely fast. As far as flushing the cooling system the commercial two part powdered flush kit made by Dupont is the best I've used. I wish him luck!

[tommag]

Yep, he's figuring on having to replace the liners. The motor is pretty fresh, but the guy he bought it from has very little knowledge. He bought it cheap, and runs his business well, so paying for repairs isn't a problem.

[runfiverun]

a good inexpensive flush would be the same citric acid we use for our brass cases.
it works great on carburetor jets too.

[jonp]

Commercial flush it. I am thinking that with the age and the straight water diet he will be in for some work, radiator first and foremost. In fact, I would have taken a look at the straight water and just ordered a radiator

[AllanD]

I would try filling the cooling system with a commercial flush and the chemical they are made of is typically either Citric Acid or Oxalic Acid.
If you wish to try something else (possibly but not certainly "milder") use Distilled Vinegar, it may take several gallons, but it is reasonable cheap at WalMart

I have experience both as a mechanic as well as having worked Chemical Technician.

I can say that the best way of removing corrosion from Iron is usually some ORGANIC acid, Such as Acetic, Oxalic or Citric, which are used because they are effective and CHEAP.
I will also comment that Malic(apples, Strawberries and many other fruits) Acid and Tartaric (typically Grapes) Acid and Ascorbic would likely work but, they are not so cheap.

these acids are also commonly used in conservation and restoration of corroded metal items (disassembled components of Coleman Lanterns)

[DougGuy]

Sulfamic acid is what I descale espresso machines with and it too would work but again commercial flushes have the corrosion inhibitor that will protect the different metals so I would use the commercial stuff and not just straight acid that you mix yourself even though it's mild.

[quail4jake]

Being used as a commercial vehicle? Consider the cost of a breakdown on the job, might do well to pull the engine, resleeve and blow the block, new radiator then fill with good anticorrosion coolant. Why do people do expensive things cheaply?

[tommag]

He's not cheap. I was just looking for the best flush. Its on it's maiden voyage for him now. It had an inframe about 100000 miles ago with non oem parts. It's using oil as though the rings never seated properly. Looks like it'll have to be rebuilt again. At 100000, it should've broken in by now.

[jonp]

He's not cheap. I was just looking for the best flush. Its on it's maiden voyage for him now. It had an inframe about 100000 miles ago with non oem parts. It's using oil as though the rings never seated properly. Looks like it'll have to be rebuilt again. At 100000, it should've broken in by now.

That stuff happens. Friend of mine just did an inframe and a week later he had to get towed back to the shop. Something weren't quite right.

[AllanD]

Sulfamic acid is what I descale espresso machines with and it too would work but again commercial flushes have the corrosion inhibitor that will protect the different metals so I would use the commercial stuff and not just straight acid that you mix yourself even though it's mild.

I have an electric appliance a sunbream"hotshot"that heats a single cup of water to boiling and it needs to be cleaned several times a year, and when time comes to clean it I run It with 12oz of undiluted Muriatic (hydrochloric) Acid you should see the deposits removed down to bare metal and the Vivid green the liquid becomes as the deposits, obviously some sort of Copper salts, are removed.

I use the same cleaning method on my tea Kettles (stainless steel "revereware" with copper bottoms) and put it onto the stove, Hot Muriatic Acid removes "Lime scale" on Contact

But you Never want to get it onto Aluminum which it dissolves nearly as fast!


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[Dave W.]

We have had good luck using the flush made by BG Products. If the truck does not have one already, have a coolant filter installed.

[Mytmousemalibu]

BG Products is right here in my hometown, so close I could see the place from my roof. They make some great products that I have faith in, no snake oils.

That said, the best flush product I have used is Mercedes Benz Citrus-flush powder. As the name implies, it is pretty much just citric acid, maybe some oxalic too. I have used just plain off the shelf citric acid powder with great results. It just flat works! I have even used it after a thorough flush with a commercial product and done the citric after and its surprising how dirty the citrus flush was. It is relatively inexpensive to do too. I was a BMW Master Tech for 10+yrs but worked on lots of euro cars and all cars in general. I am also a Coleman collector and I use it for brass parts restoration as AllanD pointed out.

I have also heard the same about big Cummins engines having problems dropping liners and the coolant ending up in the oil pan. I'd probably run something like Wix Cool additive. The older Ford/International IDI diesels had problems with cavitation & porosity and they developed special additives for that.

[tommag]

He did a complete fluids change yesterday and ran 1200 miles with no oil consumption. Looks like the goober he bought it from never changed the oil, as well as not us8ng antifreeze. While damage was surely done because of lack of maintenance, it might not be as bad as originally thought.

[john.k]

The big problem is the potential for dumping a load of glycol into the motor.When a truck can be run without AF,and just corr inhib in the water,theres no risk.Clearing a motor of a big load of glycol is a costly business.

[merlin101]

He did a complete fluids change yesterday and ran 1200 miles with no oil consumption. Looks like the goober he bought it from never changed the oil, as well as not us8ng antifreeze. While damage was surely done because of lack of maintenance, it might not be as bad as originally thought.

Geez, he pays for and in frame ($15000+) and then cheaps out on anti freeze and oil changes? DUMB goober is more like it! He probably spent all his money getting it rebuilt then couldn't afford the rest and kept going hoping to make up the shortfall, guy's like that don't stay in biz for long.

[mold maker]

I have an electric appliance a sunbream"hotshot"that heats a single cup of water to boiling and it needs to be cleaned several times a year, and when time comes to clean it I run It with 12oz of undiluted Muriatic (hydrochloric) Acid you should see the deposits removed down to bare metal and the Vivid green the liquid becomes as the deposits, obviously some sort of Copper salts, are removed.

I use the same cleaning method on my tea Kettles (stainless steel "revereware" with copper bottoms) and put it onto the stove, Hot Muriatic Acid removes "Lime scale" on Contact

But you Never want to get it onto Aluminum which it dissolves nearly as fast!


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Be careful cleaning the SS kettle because the spout on many are aluminum. My wife found holes in two of them the hard way.

[jonp]

He did a complete fluids change yesterday and ran 1200 miles with no oil consumption. Looks like the goober he bought it from never changed the oil, as well as not us8ng antifreeze. While damage was surely done because of lack of maintenance, it might not be as bad as originally thought.

100K and no oil change? Even with a secondary oil cleaner and the extended change intervals now with the newer motors that is really pushing it. What would possess someone to do that?

[tommag]

Well, jonp, the guy bought from the original owner that was leased to landstar. Apparently, he knew nothing about trucking as he was unable to make a living with it. He listed it only in craigslist and got no inquiries for a couple months. Anyhow, it's in good hands now. Jay spent quite a lot of time and money getting it ready to work. If it needs more care, it'll get it.

[leadman]

I was a Cummins mechanic many years ago. If the truck were mine I would go to the engine brand dealer and buy the flush and any chemicals recommended. On the older Cummins the chemicals were in the water filter but do not have current info on this now.

[brass410]

when I had to do mine (same issue) it was going to be a major overhaul, so we wanted to be sure of every inch, we flushed with caustic soda for about 30 mins at temp, and then neutralized, this stripped out all the rust and immediatly showed any weak spots in steel piping etc. Its surely tough on surfaces, seals, and rubber but when most is going to be replaced it doesnt matter. And it makes inspection so much easier I had a friend at machine shop and that's how they prep engines for rebuilds. It worked for me no issues, I'm not saying it's the only way, or the right way, but its was an effective solution for us.

[AllanD]

Be careful cleaning the SS kettle because the spout on many are aluminum. My wife found holes in two of them the hard way.

Thank you for the warning, but it is something I already knew

I have three that have stainless steel spouts and one with an aluminum spout