[ChevyThunder]

I was wondering if anyone could tell me if ATF is safe to use to clean carbon out of a motor. I was told by someone older that pouring a small amount of atf in your engine with it revved up a bit is a good way to clean carbon out of a motor.

I am wondering because I am trying to get the carbon out of my g/fs truck which was tuned very poorly and not run hard for a few years. I got the carb tuned but it suffers from a bit of a knock. If I turn the timing back at all it runs poorly. Thus how we got on the ATF subject.


Oh and I do realize the possibility of hydrolocking a motor cuz ATF is essentially a hydralic fluid. I was warned of this when I was told this too.

[BOBCRMAN@aol.com]

Kerosene is what we used back in the sixties. Rev the poor sick thing up to about three grand and start a kerosene drip!! SMokes like WOW! but will unstick carboned up rings and valves. Then after a few cups of Kero you switch to water. Let the motor get good and warm and repeat the first procedure.. Cleans cylinders right up..

[ChevyThunder]

alright well maybe I will do this sometime on the weekend. The motor has a cam and wasn't run very hard but had the fuel crank right up when she bought it. We put a new intake on and there was carbon everywhere and we tuned the carb using vaccuum guage and all. Thing is now it knocks at certain times... I really am getting worried this thing is going to start hurtin if I don't stop the knocking.

[jimfulco]

I had to do it a couple of times on my Nova. It makes a serious cloud of smoke, so don't do it where somebody else has to breathe it. Or where the EPA can see it. Neighbors might be prone to call the fire department, also.

Warm up the motor and set the carb on the highest fast-idle notch. Dribble the ATF down the carb SLOWLY, alternating sides so all cylinders get some. I haven't done this since ATF came in a metal can, so all I had to do was poke a couple of holes in the can with an ice pick, and it came out pretty slow. Increase the rate of pouring gradually until the engine dies, and stop pouring immediately. You won't hydro-lock it unless you pour it in real fast.

Let it sit for an hour or so, so the ATF will have a chance to soak into and loosen the carbon. Start the car, and race the engine up and down to clean out the crud. This is where the smoke comes in. If you have an appropriate stretch of road, run it through the gears a few times real hard to burn out the crud real well. Once it quits smoking, you can call it clean.

[fiscus]

You can just use water, it doesn't make the cloud of smoke atf will. And its free

[F&J]

My dad was a mechanic during the 30s-60s, he used water; I have no idea if it works, but they had to deal with a lot of carbon problems in the real old days....so maybe it does

GM makes a cleaner for that. They had to offer it because a lot of cars like the early 80s 2.5 4 cyl had the compression too high to work with the lockup converters & 2.39 gears...a little carbon and they would ping bad. It does work. Comes with instructions and was done in two steps. Supposed to get the engine real hot, pour half in running and then let it sit. Then a hard run, something like that.

I once pulled apart a 5 year old 1980 chev straight six from a pickup, and the backsides of the intake valves/stems looked like the shape of an pointed ice-cream cone. I doubt a cleaner would have worked on that. That truck would only do about 30-40 mph when floored.