Using ATF To Clean Engines
Joel Yatscoff - June 19, 2000
Rodger Boles - June 19, 2000

There's been a lot of response from members on Ricky's board to post this information on this board. This is a procedure to clean your engine using Honda automatic transmission fluid. I deserve no credit for the following information I'm just a courier of information I orignally obtained from Rodger. This procedure does work. I did it on Saturday. It is not however a mircale cure all. My compression was always good (ZC - 170psi in every cyl.) but I was having a oil control problem. Even though I also did my seals on Sunday I did notice improved oil control and my car ran significantly smoother. I guess results depend upon the shape of your engine. Anyways, here it is:

This is an extrememly messy job for the shade tree mechnaic. At one point, while trying to soak up the ATF from the cylinders (as per Rodger's advice) I slowly cranked the engine over with a socket on the crank pulley. Well it obviously wasn't slow enough because a geyser of red fluid shot out of cyl. #1 hit the top of the underside of the hood and split with half falling into my hair and the other half the entire engine bay. Needless to say, it was very messy and my parents were the happiest (Happy Father's Day?)

I have some additions to Rodger's procedure.

#1. Wax your rear bumper very well before you do the procedure. Don't ask you'll understand if you do it.

#2. Buy a bag of kitty litter. Again don't ask.

#3. After you saok up the ATF drive it out of town where nobody will know you or your car.

#4. Buy some engine cleaner.

#5. Buy or find a syringe. Attach some small diameter tubing (I used that fish tank stuff for the air pump). This is the BEST way to remove ATF from the cylinders. (Editor's Note: Rodger later suggests a turkey baster to remove the ATF)


Buy 2 liters of ATF.

Fill it up to the top so the valves soak too....they get carbon on them also. yes, some will likely flow back into the intake and exhaust ports, but not enough to be any kind of will just loosen the carbon built up behind the valves.

Set the car at TDC, then go an additional 90 degrees on the crank and the piston tops should be all the same height.

Don't worry about leakdown too should still have most of the ATF in the cylinder after 24 hours have elapsed. After you vent all the ATF out (the first couple squirts will make a mess if you miss the rag) the car is going to purge a lot of ATF through the exhaust ports and it will linger in the upper exhaust system until it gets hot enough to burn out. This means the car will smoke for quite a while. hehehe.....people will think you're James Bond.

If you have a significant drop in the ATF level after 24 hours in any cylinder, i would recommend changing the oil before you go for a spin, so as to not over-contaminate the engine oil and wear out the bearings. This shouldn't happen, but I'm just making sure you know what to do if it does.

The ATF precedure is simple.....pull the plugs, set the engine so the piston tops are all about the same height, pour in ATF until it's full to the top of the plug threads. Let sit for 24 hours or so. The ATF will seep down through the ring gaps and soften the carbon freezing up your oil rings.

After you're done, put rags down in the plug holes and crank the engine one little bit at a time.....let the rags soak up the oil.

After the rags are soaked, spin the engine freely to throw out as much ATF as possible. When the cylinders are reasonably cleared out put the plugs back in and fire it up.

Get your gas mask. Drive it HARD while the rings are still loose to help blow the carbon out of the oil rings. if some ATF seeped into the crankcase, it's will help the rinsing process.

Don't drive more than 50 miles on the ATF-contaminated oil, then change it. Hopefully it will help free-up the oil rings, but your good-compressing compression rings will be working against it.

Good luck! If you want to run a cleaner in your engine full-time, get some mobil 1 syntheitc 0-30 and a bottle of Rislone (see your Honda dealer). We use that to clean out gunked-up passports.