I came across this today. Since the old-school habit of adding a quart of ATF to engine oil just prior to oil changes keeps coming up on this board (and elsewhere), I thought this interesting. It would seem that other products have significantly better solvent qualities for such purposes, be they high-tech (Auto RX), or low tech such as kerosene (Valvoline/Pyroil Engine Flush) or diesel fuel (Gunk/Solder Seal Engine Flush).
"MYTH: Adding a quart of ATF the day before an oil change will clean your engine. ATF added to the motor oil will clean the engine due to the high levels of detergent in ATF."
"FACT: ATF does not contain detergent chemistry. ATF does contain dispersants, which have properties similar to detergents. But ATF is not formulated to withstand the combustion environment inside the engine." http://www.quakerstate.com/pages/carcare/whattoknow.asp
For the record...
Detergent: "...an additive -- usually metal-organic chemicals...that helps keep oil-insoluble materials in colloidal suspension...A detergent is normally used in conjunction with a dispersant."
Dispersant: "...an additive, usually organic polymer containing nitrogen groups, that help keep deposit precursors finely dispersed in the oil so that they cannot form oil insoluble materials that can settle out of the oil. Dispersants are usually used in conjunction with detergents."
http://www.dcpetroleum.com/definitions.html
And before it comes up, I'm not suggesting that everyone use flushes of ANY type unless they're actually needed. Sneek a peek through the oil filler cap before deciding same -- oil firms agree that the best flush for a clean engine is no flush at all, just change the oil.
[ February 10, 2004, 08:29 PM: Message edited by: TC ]