Trans fluid to clean engine?

Scott Long

Registered User
Guy at work says to get my engine cleaner inside instead of using the oil detergent additives that I should pour in a qt. of trans fluid and run it for a while, then drain the oil and change the filter.

I noticed that as my car is getting up in the mileage the oil comes out very dark when I change it. I can check it right after changing it and it's not exactly gold and clean looking. When I did the head gaskets the top end was very clean but I didn't pull the pan and check out the bottom end of the engine.

Any of you heard of using trans fluid? I know it has a lot of detergent in it as a transmission is one of the cleanest things you can take apart. But what viscosity is Dex III and would it do more harm than good if I put it in the engine for say 30 minutes or so? Would it even make a difference?

We have some stuff at work that says run for 5-6 minutes and then drain the oil. It's really watery clear stuff you pour in right before you drain the oil. I would hate to wash off the bearings and destroy my old engine.

Any suggestions for cleaning the engine besides a tear down and rebuild?
 
you can use diesel to clean it also.... just dont run it for a long time, just about a minute or less and watch the crap come out...
 
I don't think I'm going to put diesel fuel in my oil fill of my engine. Trans fluid maybe but I don't want to be back on here posting "Guys, whatever you do, don't use a qt. of trans fluid to clean your engine!!!"

Get my drift.
 
well let me see... i used it on mine... and guess what... it still runs strong... but what do i know, i have only tried it...
 
I have used trans fluid in many engines, and left it in there for the entire oil change interval, and have never had a problem. It does clean the internal engine parts very well.
 
you can use diesel to clean it also.... just dont run it for a long time, just about a minute or less and watch the crap come out...
on a asimilar note, my dad said they used to drain a Qt. Of oil and put a Qt. of kerosene in, Run it for a couple of minutes and drain.

he also says high milage engines would leak like sieves for a couple thousand miles:p I guess all the little holes that formed in the oil pan gasket had gotten filled in with "oil gunk". Using the kerosene cleaned all that gunk out, and the holes weeped for a while until they plugged themselves up again....or something like that. i would imagine that any method you use to clean the engine will yield similar results.
 
i have heard of the trans fluid but never any other i dont know if it will work . let me know ill give it a try if its safe.;)
 
you can get stuff thats actually meant for cleaning running engines for less than 6 bucks, i think spending a couple bucks now is worth more than POTENTIAL engine damage later on!
 
it cleans out the crap, you run it for a while before you do an oil change... just go down to autozone or kragen and read the label...
 
Transmission fluid

Tranny fluid is the best and safest detergent you can put in your engine. Ive used it to clean up the internal engine and ive even used it to unclog the oil pick-up screens. Works very well with no ill effects.
 
so do you run straight tranny fluid or a mix? Do you mix tranny fluid with the dirty oil then run it and drain it? Can anyone give better instructions and quantities? and how long to run it? I see one person ran it for the entire oil cahnge interval, whats that 3000 miles on your car? Just curious as I have heard of using tranny fluid as well. Also any tranny fluid or a specific type? LIke Dexron III, IV, Type F, synthetic, etc etc.
 
so do you run straight tranny fluid or a mix? Do you mix tranny fluid with the dirty oil then run it and drain it? Can anyone give better instructions and quantities? and how long to run it? I see one person ran it for the entire oil cahnge interval, whats that 3000 miles on your car? Just curious as I have heard of using tranny fluid as well. Also any tranny fluid or a specific type? LIke Dexron III, IV, Type F, synthetic, etc etc.

The way I was told and did it years ago, was to use 1 qt of tranny fluid and the rest oil and then only go for 500 miles and then change the oil and filter. There were no adverse effects to my 350 ci Camaro. I have not done this to any of my SC's.
 
When I bought my Thunderbird Turbo Coupe, I had to change the valve cover gasket. The area under the valve cover was gunked up and nasty. I put trans fluid in several times in the place of oil, not the entire amount, just 1qt. I had to remove the head 80,000 miles later for a burnt valve, and the head was clean as if it was brand new. I never had a problem with it. You can also use trans. fluid to clean your valves, but if you don't know what you are doing you can ruin an engine quick.
 
Just so you know, mercon fluid has a viscosity similar to 30 wt. oil, so you could run the engine with nothing other than trans fluid in the oil pan, and it would be perfectly fine.
 
Scott.

You want to do a double treatment of auto-rx.

It will clean up that motor over time.

Read more on bobistheoilguy.com.

I used it on several sludged up motors with good results.

It involves a couple quick oil changes.

JH
 
Whenever I see a post like this, its all I can do to bite my lip, but I always feel its my duty to set people straight on this stuff.
First of all: ATF does NOT have any detergent in it, no matter what you may have heard from everbody over the years. That is an "old wive's tale".
It definately will clean the oil system somewhat, but that is only because it has a higher solvency ratio than any motor oil you may put in your engine...specially if you have sludged-up, old and viscous oil in there.
'regular' ATF, like Dexron/Mercon, and Type F are all single-grade, a straight 10-weight dino oil.
The newer ATFs, like Mercon-V, ATF+3/4 and Dexron-VI are all synthetic blends, and multi-viscosity, 5W-10W-10.

While kerosene will also definately clean the oil system, that is really a crap shoot...like playing russian roulette with your engine.
Kerosne is one of the heaviest solvents there is, and any solvent...especially kerosene, acts to cut the lubricity of any more-viscous (less solvent) fluid it combines with.
The problem is that the solvents 'cut' the hydro-dynamic boundry layer of lubrication off the linear friction surfaces inside the engine, promoting excessive wear. This may not show up as any noticeable damage for many thousands of miles...or it may show up today with a seized engine. You never can tell, as all engines with lots of miles on them are unique, and there is no way to predict what will happen.
The preferred way to clean a sludged-up motor is to use something made for that purpose, a dedicated oil-sysytem cleaner. A good quality cleaner has a mild solvency formulation, and also has a very shear-stable yet lightweight oil base to maintain a good HDBL during the cleaning. Basically it emulsifies (melts) the soft sludge deposits, and the now-liquified sludge will be held in suspension in the old oil as it is drained out.
It is impotant to remember that it takes many thousands of miles to get an engine sludged-up enough to need a product or procedure such as this, so it is unrealistic to think that a single application of any cleaner is going to remove all, most or even a significant amount of the stuff and be safe while doing so.
Running a cleaner before an oil change for maybe 5-10 oil changes in a row is not un unrealistic thing to do for a mildly dirty engine. Its the safest way.
Be careful about what you buy in the auto store to clean with though...they are not all the same, and some are downright terrible for your engine. For instance, 'Gunk 5-Minute Motor Flush' is nothing but a qt. of kerosene, as is 'Pyroil Motor Flush'.

I fully expect some here to claim "Bull~~~~" on me, and I have had this discussion many times before, but I encourage evryone to stop repeating the same old crap you have heard second, and third-hand from other 'experts' over the years, and actually talk to a real expert: Call the 1-800 # listed on the back of any brand of oil you may use...they all have engineers just waiting by by ht ephone to answer all your technical questions. You will be amazed at the stuff you can find out just by asking the right person.

Let the arguments begin!
 
So you telling someone that adding a tank of a certain type of fuel to fix their sticking fuel sender as a miracle fix is ok though?
 
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