Recently, my neighbor who is a retired tranny tech(still a sharp cat and knows his stuff at 69yrs old!) runs a quart of clean auto tranny fluid in his engine crankcase for a handful of miles just before changing his expired motor oil; says the detergents in the atf do a beautiful job cleaning out sludge and he's never had any problems as such...feels its much safer than the kerosene/solvent type flushes such as made by Gunk corp. I've heard other old timers doing this before but only for 15-30 minutes,idling. I recently installed auto-rx in 3 of our vehicles for deep cleaning, but am curious as to the positive effects or harm of flushing with ATF when nothing else is available...
Use of ATF as a motor oil flush
- Thread starter buddy-lee
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Bad move. 50 years ago trans fluid had more detergents than motor oil.
Todays motor oils have much more detergents than trans fluid.
Some old habits never die.
Todays motor oils have much more detergents than trans fluid.
Some old habits never die.
Hey,
Sometime ago when I was only starting to care about clean engines and using good oil, I did this to my old truck which was a 91 F150 with the 300 I6. I heard about this procedure, tried it, didn't notice any negative side effects but probably caused alot of wear on my engine at the time.
Since coming here at BITOG, there are much better cleaners out there such as LC, and Auto-rx,,,,,AR
Sometime ago when I was only starting to care about clean engines and using good oil, I did this to my old truck which was a 91 F150 with the 300 I6. I heard about this procedure, tried it, didn't notice any negative side effects but probably caused alot of wear on my engine at the time.
Since coming here at BITOG, there are much better cleaners out there such as LC, and Auto-rx,,,,,AR
Just thinning down his oil.....for no real reason other than the now thinner oil just flushing a bit.....I would think the same thing would happen with a 5W-30, and you still would have the proper AW adds.
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That should have been on the combustion side of things though, kenw. That's how it was discovered as a combustion deposit cleaner ...bad vac mods. That cylinder would be buffed ..the others carboned up (the vac mod was usually tapped into one runner of the intake) ATF does a great job on combustion deposits ...but does produce the smoke screen that would have been adventagous on D-Day. This fell out of vougue with several generations having FI engines where deposits are, for the most part, a non issue for up to 100,000 miles. Neither were the norm in the 60-70s when this pratice was in use.
Many here still consider it a falsehood, in spite of never actually seeing any effects, either good or bad, since they've never experienced it. That is, their attitude is as much a myth as they condsider it myth.
As far as a "flush" for the oil? It was used as a thinning agent and actually factory recommended by Chevy during the early 70s to cure lifter tap on some SBC V8s. That, as was mentioned, was a long time ago and oils have experienced quantum leaps in improvements over that time span.
Many here still consider it a falsehood, in spite of never actually seeing any effects, either good or bad, since they've never experienced it. That is, their attitude is as much a myth as they condsider it myth.
As far as a "flush" for the oil? It was used as a thinning agent and actually factory recommended by Chevy during the early 70s to cure lifter tap on some SBC V8s. That, as was mentioned, was a long time ago and oils have experienced quantum leaps in improvements over that time span.
MolaKule
Staff member
The only ATF that would be of any use as a flush would have been the Type-A ATF (circa 1940's), which once had loads of adds plus kerosene. Otherwise, you are just thinning the oil with a fluid that has 1/5 the AW and detergent adds of any cheap motor oil.
Better to do a flush with LC or some other cleaner that has a better viscosity retention factor during the flush.
Better to do a flush with LC or some other cleaner that has a better viscosity retention factor during the flush.
An older friend suggested the ATF flush to me 3yrs ago. I did it to an 88 Grand Am 2.5L-4cyl w/ 120,000 miles. The engine may not have been maintained very well, and I wanted it clean. During the flush with ATF, and forever after, the engine had a terrible knock or piston slap that it didn't have before doing the ATF flush. I would not do it again. Also, I did the B-12 Chemtool in the crankcase flush on a higher mileage car, that also did nothing but have a slight knock forever more. Now, I use a HDEO, when temps allow, and perform short OCI's. However, after learning about Auto-RX, that is the way to go for the next used vehicle I get.
Look at ARX, maintains oil spec, cleans while you drive. Its the best cleaning choice.
"MYTH #12: 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. Quaker State® recommends that you keep the fluids where they belong: motor oil in the crankcase, and automatic transmission fluid in the transmission."
http://www.quakerstate.com/pages/carcare/whattoknow.asp
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. Quaker State® recommends that you keep the fluids where they belong: motor oil in the crankcase, and automatic transmission fluid in the transmission."
http://www.quakerstate.com/pages/carcare/whattoknow.asp
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