Using ATF to clean out sludged engine?

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Everywhere on the internet, whenever someone posts valve cover pics of a sludged engine, people start suggesting the use of ATF in the engine to clean it out because it is loaded with detergents. This myth has been perpetuated for decades it seems, but has anyone actually verified the claim?

When I see ATF VOAs, there isn't much calcium or magnesium, so where did the high detergent myth come from? I don't see the reason why ATF would need lots of detergents since the gearbox isn't exposed to combustion byproducts, so shouldn't motor oils contain more detergent?

I also see people suggesting the use of diesel instead to clean out sludge which seems more viable since diesel is a good solvent.
 
Originally Posted By: HKPolice
Everywhere on the internet, whenever someone posts valve cover pics of a sludged engine, people start suggesting the use of ATF in the engine to clean it out because it is loaded with detergents. This myth has been perpetuated for decades it seems, but has anyone actually verified the claim?

When I see ATF VOAs, there isn't much calcium or magnesium, so where did the high detergent myth come from? I don't see the reason why ATF would need lots of detergents since the gearbox isn't exposed to combustion byproducts, so shouldn't motor oils contain more detergent?

I also see people suggesting the use of diesel instead to clean out sludge which seems more viable since diesel is a good solvent.



Everywhere on the internet there are idiots!

ATF does not contain detergents as far as I am aware and it might not be compatible with the oil seals or gaskets in an engine.
There is a case for using diesel fuel to rinse out a diesel engine, but not for use with the engine running. Diesel fuel might dissolve sludge, BUT it will not dissolve varnish deposits.

Use a major brand flush additive and avoid the use of the drive around versions like MMO if your engine has a turbo fitted. Liqui Moly who area about the best company making oil additives say that if you use their drive around oil system scourer (It's a better version of MMO) in an engine that is badly sludged, the sump and oil feed intake screen should be cleaned first. The RPM should also be kept low when in use (Also mentioned by Liqui Moly in their PDS).
 
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Yes-lots of well written junk on the net as well as poorly written truths. The ATF detergent myth just seems to hang around. I've used diesel several times, but very carefully. I think it's best to scrape valve covers and pans first and to clean the pick up screen. Those have the most sludge.
 
Originally Posted By: HKPolice
I also see people suggesting the use of diesel instead to clean out sludge which seems more viable since diesel is a good solvent.

It also isn't a lubricant so I have no idea why anyone uses that either.
 
I wouldn't do anything to quickly clean a sludger.

No Kerosene, ATF, or crancase additives.

If you bust loose a bunch of crud you may block the oil pickup screen and starve the engine.

Just run a good "cleaning" oil that meets your spec such as Pennzoil Yellow Bottle and run that with normal OCIs IMHO.
 
Originally Posted By: UltrafanUK
Originally Posted By: HKPolice
Everywhere on the internet, whenever someone posts valve cover pics of a sludged engine, people start suggesting the use of ATF in the engine to clean it out because it is loaded with detergents. This myth has been perpetuated for decades it seems, but has anyone actually verified the claim?

When I see ATF VOAs, there isn't much calcium or magnesium, so where did the high detergent myth come from? I don't see the reason why ATF would need lots of detergents since the gearbox isn't exposed to combustion byproducts, so shouldn't motor oils contain more detergent?

I also see people suggesting the use of diesel instead to clean out sludge which seems more viable since diesel is a good solvent.



Everywhere on the internet there are idiots!

ATF does not contain detergents as far as I am aware and it might not be compatible with the oil seals or gaskets in an engine.
There is a case for using diesel fuel to rinse out a diesel engine, but not for use with the engine running. Diesel fuel might dissolve sludge, BUT it will not dissolve varnish deposits.

Use a major brand flush additive and avoid the use of the drive around versions like MMO if your engine has a turbo fitted. Liqui Moly who area about the best company making oil additives say that if you use their drive around oil system scourer (It's a better version of MMO) in an engine that is badly sludged, the sump and oil feed intake screen should be cleaned first. The RPM should also be kept low when in use (Also mentioned by Liqui Moly in their PDS).

Nuff said!
 
Originally Posted By: HKPolice
so where did the high detergent myth come from?

"70% detergents, which keep the valves free inside an automatic transmission" at 3:06
 
I never heard anyone say ATF is loaded with detergents, I think it was more at it was a fatty oil.

Back in the day (early 70's and prior) it was a fatty ester derived from marine mammal brain lube (NO, REALLY!).

Now they use low flash naphthenic base on the vanilla flavor low spec stuff - as is gearbox oils.

Not your typ Paraffinic base used in most engine oils (exception would be HP synthetic spec fluids)

Maybe Molekule could speak to natural solvency and scavenging of ATF lubes - I once knew and have now forgotton
frown.gif
 
A lot of people just don't get "correlation doesn't imply causation."

From the day automatic transmissions came out, people would open them up and see sparkling clean interiors except for a little clutch dust on the bottom of the pan. So OBVIOUSLY it must be because that automatic transmission fluid has incredible, magical cleaning properties.

No, its just that automatic transmissions don't generate the nasty chemicals that internal combustion engines do.
 
A good diesel oil like delvac has more detergent in it than its automotive counterpart.

Before I tried any additive type products I'd run a few short OCI's on it.

UD
 
Originally Posted By: UncleDave
A good diesel oil like delvac has more detergent in it than its automotive counterpart.

Before I tried any additive type products I'd run a few short OCI's on it.

UD
Delvac is a heavy duty engine oil suitable for use in both diesel and gasoline engines.
 
ATF doesn't need too much detergents, but need a lot of dispersants, to keep the dirt to accumulate at crannies and valves. People often confound detergents with dispersants. ATF have dispersants to lift and spread the particles avoiding accumulation in narrow passages. That is helpfull in the cleaning process of an engine. Dispersants doesn't show up in uoas, since they're succinimides and has no metalic elements like Ca, Na, Bo or Mg on it.
 
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Originally Posted By: HKPolice
Everywhere on the internet, whenever someone posts valve cover pics of a sludged engine, people start suggesting the use of ATF in the engine to clean it out because it is loaded with detergents. This myth has been perpetuated for decades it seems, but has anyone actually verified the claim?

When I see ATF VOAs, there isn't much calcium or magnesium, so where did the high detergent myth come from? I don't see the reason why ATF would need lots of detergents since the gearbox isn't exposed to combustion byproducts, so shouldn't motor oils contain more detergent?

I also see people suggesting the use of diesel instead to clean out sludge which seems more viable since diesel is a good solvent.


Hey HKPolice - We cannot recommend using an automatic transmission fluid to clean out sludge in engines. ATFs contain friction modifiers, detergents, dispersants and other properties that are not designed to be used in an engine. If you are having a major sludge issue, we suggest you have your engine professionally flushed by a certified technician. Additionally, Pennzoil has a high mileage motor oil that could help eliminate these problems. Pennzoil High Mileage Vehicle helps prevent dirt and contaminants from turning into performance-robbing deposits, but also cleans out sludge. It cleans out up to 40% of engine sludge in the first oil change and continues to clean in the second oil change. It also provides enhanced protection for worn engine parts and helps condition engine seals. Hope this info helps! - The Pennzoil Team
 
Originally Posted By: Ohle_Manezzini
ATF doesn't need too much detergents, but need a lot of dispersants, to keep the dirt to accumulate at crannies and valves. People often confound detergents with dispersants. ATF have dispersants to lift and spread the particles avoiding accumulation in narrow passages. That is helpfull in the cleaning process of an engine. Dispersants doesn't show up in uoas, since they're succinimides and has no metalic elements like Ca, Na, Bo or Mg on it.


Now that is interesting. I have never seen that explanation before. Thank you!
 
This all started back in the 1940's when the original HydroMatics came out. Back then "ATF" was made with fish oils (OK, Whales are mammals...). They acted just as AutoRX claims to do nowadays with animal fats (Lanolin's) to break down petroleum compounds. The fish oil was pretty potent against some kinds of deposits.

But, around the late 1950's all the natural oils were being replaced with pure petroleum products. They had figured out how to make petroleum oils that allowed the clutches to stick and work well. So away went the natural oils. And away went the cleaning capabilities.

Put a pan of used ATF outside and nothing will happen. Do that in 1954 and neighborhood cats would come sniffing around
laugh.gif
 
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Just for clarity, Spermaceti oil (whale oil) was collected from a large sound-focusing organ located in the front of head. This organ is not the brain. Most industrial uses of spermaceti were banned in 1972 in the Unites States. After it was banned, development of alternative products accelerated, including other animal-based products. The main ingredient in LubeGard is claimed to be the first synthetic replacement for spermaceti oil in ATF applications.
 
Originally Posted By: Falken
I wouldn't do anything to quickly clean a sludger.

No Kerosene, ATF, or crancase additives.

If you bust loose a bunch of crud you may block the oil pickup screen and starve the engine.

Just run a good "cleaning" oil that meets your spec such as Pennzoil Yellow Bottle and run that with normal OCIs IMHO.


A good cleaner oil will clean out sludge deposits after several OCI's, BUT it will not shift top end varnish deposits. If you have such deposits in a turbo feed line they can easily cause premature failure of the turbo bearings.
I have used flush additives from major oil companies that are designed for use at idle only to good effect a few times, they are safer to use than drive around oil scourers, but can still cause any pre existing oil leaks to get worse for a while.
Obviously dropping the sump to clean it and the critical oil pump intake screen is a great idea, but it can be a PITA with some more modern engines, as it might involve moving exhaust down pipes or cross members etc.
 
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Originally Posted By: HKPolice
Everywhere on the internet, whenever someone posts valve cover pics of a sludged engine, people start suggesting the use of ATF in the engine to clean it out because it is loaded with detergents. This myth has been perpetuated for decades it seems, but has anyone actually verified the claim?

When I see ATF VOAs, there isn't much calcium or magnesium, so where did the high detergent myth come from? I don't see the reason why ATF would need lots of detergents since the gearbox isn't exposed to combustion byproducts, so shouldn't motor oils contain more detergent?

I also see people suggesting the use of diesel instead to clean out sludge which seems more viable since diesel is a good solvent.


The reasoning pre-dates the Internet experts, as BrocLuno and GMorg said. I first heard this in the late eighties, from a mechanic who probably built his first engine in the early or mid-sixties. It wasn't an answer to sludge necessarily, but he said adding ATF when you're one quart low would help clean an old engine. When I blew a head gasket, he had me flush it out with diesel instead of pulling and tearing down the whole engine.

He was also saving a bottle of "whale oil" limited slip friction modifier for a special project.
 
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