monoblanco
Aluminum
- Joined
- Aug 19, 2005
- Location
- Bay Area, CA
Greetings & Happy New Year -
An aquaintance, one whose theories I frequently have doubts about, strongly recommends that when a car's engine oil is down by one quart it be topped up with a quart of ATF. He claims that this will do an excellent job of "cleaning out" the engine - of sludge, I guess he means - he tends toward vagueness and generalities when asked for details on why this should work, but is adamant that it does.
I'm pretty skeptical on a couple of counts.
First, as I understand them, the roles of ATF and motor oil are quite different - motor oil needs to have excellent lubricity to protect the many sliding interfaces in an engine, pistons to cylinder walls and rod bearings to crankshaft just to name a couple, and also to contain detergents and neutralizers to deal with the products of combustion, such as acids and soot, while ATF actually requires a limited and controlled level of lubricity so that wetted clutches and bands in automatic transmissions can grip without excessive slip and so that synchronizers in manual transmissions, most of which now call for ATF, can operate with enougn friction to sychronize. In fact, it's my understanding that an automatic transmission cannot operate properly with motor oil in it due to clutch and band slippage. Also the compounding of ATFs need not be concerned with the harsh problems posed by combustion product blowby.
Second, it seems very unlikely on the face of it that ATF contains a better additive package for keeping an engine sludge free than does a good quality motor oil formulated with sludge control as one of its primary objectives - sort of like the old claim that a roll of toilet paper could make a better oil filter than a product specifically designed to filter oil - I never bought that one either.
Recognizing that even at my age I may still be able to learn something new, and remembering that once or twice in the past I've been mistaken, I'm asking fellow forum members if they know anything about this topic. I'd be particularly interested in information, pro or con, that you are aware of from reputable engineering sources in the automotive or motor oil industries.
Hope some of you can offer worthwhile thoughts on this.
Thanks, Monoblanco
An aquaintance, one whose theories I frequently have doubts about, strongly recommends that when a car's engine oil is down by one quart it be topped up with a quart of ATF. He claims that this will do an excellent job of "cleaning out" the engine - of sludge, I guess he means - he tends toward vagueness and generalities when asked for details on why this should work, but is adamant that it does.
I'm pretty skeptical on a couple of counts.
First, as I understand them, the roles of ATF and motor oil are quite different - motor oil needs to have excellent lubricity to protect the many sliding interfaces in an engine, pistons to cylinder walls and rod bearings to crankshaft just to name a couple, and also to contain detergents and neutralizers to deal with the products of combustion, such as acids and soot, while ATF actually requires a limited and controlled level of lubricity so that wetted clutches and bands in automatic transmissions can grip without excessive slip and so that synchronizers in manual transmissions, most of which now call for ATF, can operate with enougn friction to sychronize. In fact, it's my understanding that an automatic transmission cannot operate properly with motor oil in it due to clutch and band slippage. Also the compounding of ATFs need not be concerned with the harsh problems posed by combustion product blowby.
Second, it seems very unlikely on the face of it that ATF contains a better additive package for keeping an engine sludge free than does a good quality motor oil formulated with sludge control as one of its primary objectives - sort of like the old claim that a roll of toilet paper could make a better oil filter than a product specifically designed to filter oil - I never bought that one either.
Recognizing that even at my age I may still be able to learn something new, and remembering that once or twice in the past I've been mistaken, I'm asking fellow forum members if they know anything about this topic. I'd be particularly interested in information, pro or con, that you are aware of from reputable engineering sources in the automotive or motor oil industries.
Hope some of you can offer worthwhile thoughts on this.
Thanks, Monoblanco