This isn't the sort of thing that most people have first hand experience with so we're all making educated guesses here. Having said that, I'm in agreement that it's likely to be fine. It's not good and it probably shortened the engine life a little but as Bob indicated it's probably something like reducing it from 350k to 320k.
wheelsmithy (Joe-with-an-L) (Forum Supporter) said:Should be fine. I knew guys who would run straight ATF in their heavily abused V8s as a "Clean Er Out" cycle in oil changes. Meaning, run til it is oil change time, then back to oil. I did not see these engines after say, 10K miles, but I bet it's fine.
I stand corrected. Some of us do have first hand experience with this!
In reply to wheelsmithy (Joe-with-an-L) (Forum Supporter) :
I ran anywhere from 20%-80% ATF in my Saturn(s) more times than I can count as a clean out cycle, for fairly extended periods of time. No issues.
I don't know how effective it really was at cleaning anything though.
In reply to ProDarwin :
Depends on the fluid you were using. Seriously. A lot of the newer fluids don't have the same amount of detergents the older DEX III type fluids used. They have different priorities. It was amazing watching the formulations changing right before my eyes
In reply to bobzilla :
Yeah, thats what I heard as well. I remember reading/hearing someone mention that a lot of oils actually have a lot more detergent than ATF - which kinda makes sense to me, as ICE oil is a much dirtier thing than ATF which is just circulated inside a sealed case and subjected to a little heat and pressure.
I think you will be fine. Maybe put a scope in the pan drain plug hole and see if the pickup has crud loosened up by the ATF.
Other than that have them do 3-4 oil changes for you. I would drain it and then fill it with cheep oil and run it with out load for 20-30 min and then drain and fill again with good oil. I would do two or three more changes 200-400 mile intervals (all with new filters) with oil testing to make sure that nothing is going south. If all the tests come back good I think you are good to go. I would sell the oil tests to the shop owner as a way for him to also know that the motor is good moving forward. That way everyone can be happy. If testing comes back with bearing material in the oil it is time to start talking motor rebuild / replacement and insurance claim. By doing the testing there is a quantifiable justification for either doing nothing or pursuing action now.
Back in the 80's I/we actually ran motors on 90-100 percent ATF for a couple hundred miles leading up to oil changes (got to love SBC and BBC motors) with no ill affect that I know of.
Oh and while I am thinking of it did they do the trans fluid change for you that they were supposed to do originally upon the trucks return to them? Also I assume that they refunded your $$$ and will be doing all this on there dime. It is the least they can do for you. Considering you don't seem to be one of "those people" that would be hopping up and down screaming that you need a new motor.
And lastly yes get it in righting from the owner of the shop acknowledging the error so you have recourse down the road should the motor have any oiling related failure in the near future. If they are a good shop they will understand that it is in there best interest to notify there insurance of the event to provide you and them coverage in he future should things go south. The notification to the insurance company could include the course of action being taken noting the testing. The shop owner may want the insurance to see the test results (good or bad) if you pursue notification of them.
BUT as I said earlier other than inspecting the pickup for sludge / crud the ATF cleaned out of the motor I think you will be fine. And you got probably one of the best motor flushes possible for free. :-)
In reply to dean1484 :
Yes, they are doing the trans flush that I had originally requested and this is all on their dime- what you've described is pretty close to what the current plan is, and it was suggested by the shop owner. I'll be sure to ask the insurance question next time I talk to him. I think it's in both his and my best interest to be cool about this, I live within walking distance of the shop and neither of us is planning to move so continuing to get along would be a good thing.
My only concern would be sludge on the pickup screen.
As long as your oil pressure is good with current oil, you are good to go.
Inexpensive scopes can be purchased on amazon these days. In case you don’t have one.
I took an adult education class on car maintenance about 30 years ago where the teacher recommended desludging an engine by running 2 quarts of ATF for 50 miles. He claimed it would clean out paraffin-based oils particularly well.
I've run ATF instead of motor oil for hundreds of miles in a turbocharged four cylinder engine in a midsize car. (The S40 that I used to rallycross/tow with) Cleared all SORTS of gunk out of the crankcase and other places. And then I'd drain it out and put ATF in it again.
You'll not only be fine, but the engine will come out better for it.
The low oil pressure is most likely because the overfull crankcase was getting whipped by the crank, and foam in the oil pan is not conducive to good oil pressure.
I have to add that my ATF stories date back to the early 90s/ late 80s, so may not apply to modern equipment.
Funny, I just added a quart of ATF to a junk miata I drove hom Sunday. No, that's not relevant at all.
Good luck Nonack.
You had your engine filled with red 5W20. Sludged up old American v8's have been known to get that treatment to shut up sticky hydraulic lifters in my shop.
The oil pressure dropping off at higher speeds was from frothing oil from being overfull.
Go yell at the oil change place and move on with your life.
So, basically this was the best mistake ever! Yay!
What happens if the engine is accidently filled with synovial fluid? 50 more horsepower?
Geeeez, great oil shop. There are basically only 2 things to do (aside from a filter) in an oil change. Put the right kind of oil back in and the right quantity........and they got them both wrong.
Feedyurhed said:Geeeez, great oil shop. There are basically only 2 things to do (aside from a filter) in an oil change. Put the right kind of oil back in and the right quantity........and they got them both wrong.
Transmission flush machines are basically a piston in a cylinder, or a tank with a diaphragm, with clean transmission fluid on one side. You connect the machine inline with one of the trans cooler lines and run the engine, and the transmission pumps its fluid into the other side of the piston/diaphragm, forcing clean fluid back in to the transmission.
GMs have oil coolers in the radiator, like a trans cooler. Sounds like they connected to the 5/8" lines on the driver's side instead of the 3/8" lines on the passenger side 
D'oh. "Wow, the fluid coming out of the trans is REALLY DIRTY, look how black it is!!"
I'm a little curious how the engine ended up being overfull, the machines are normally pretty good about maintaining fluid levels because they can only put in what comes out. But, hell, I wasn't there.
Antihero (Forum Supporter) said:There are people that say a 50/50 mix of atf and oil will help desludge an engine. I've never tried it.
Isn't ATF about 30w oil in viscosity? I mean, it's put in manual transmissions so I assume it can lubricate somewhat well and it's used to higher temps.
I'm not sure its the worst thing ever, I definitely wouldn't do it on purpose
Dex3/Merc is about 20w
The whole de-sludging an engine thing is such a myth that needs to die. People drain black sludgy oil from their crankcase at 5000 miles and think it's gross, then drain a trans pan and see mostly clean ATF at 60k and think it's because the ATF has better cleaning properties. First, it doesn't. ATF has fewer detergents than motor oil. Second, engines have constant blow-by and serious contamination from combustion. Third, if ATF had more detergents, the fluid would be holding even more sludge because it would wash it out of the transmission. Complete myth. Dare I even say, complete bullE36 M3. Adding ATF to a crankcase to clean the engine is like saying "these dishes are extra greasy, so I'll wash them in just water and not use soap."
Having said that, there is likely zero damage from the ATF in the crankcase. Regardless of the fact that ATF in an engine doesn't do anything for cleaning it, millions of engines have been flushed with ATF and lived a perfectly happy life. They're no cleaner, but they're fine.
Had you not noticed and ran it for 3000 miles, then yes. You would be hiring a lawyer. ATF doesn't have the high-shear and filming additives so I would expect bearing wear, possibly cylinder/ring wear, and it would likely kill a flat-tappet cam rather quickly.
In reply to Curtis73 (Forum Supporter) :
To sidetrack for a moment, 'cause I very much like debunking old wives tales in the automotive world, I have a question. I have never used ATF to clean the inside of a gasoline engine. I have used it to degrease dirty parts and it does a better job than engine oil. Of course engine oil will do a little bit of cleaning parts as well. There are just so many better options!
The way I learned it, the detergents in oil are there to keep any dirt in suspension, so the in line filter can filter them out. In small engines with no pressurized filter system, Non detergent oil is recommended so the contaminates will drop to the sump, and come out with the next oil change. Not that the detergents in engine are there to clean anything.
Even though I did not see a place for a question mark, (I suck at proper english) this entire post is intended as a question Thanks
If the detergents in engine oil could dissolve the sludge, it wouldn't be there in the first place.
Sometimes you need to use a different additive package.
Also. This was 100 miles of ATF.
The 3000 mile old oil filter, running with engine oil, did not look dirty.
I continued to change the filter at 100 mile intervals for a while until it stopped doing, well, THAT. Then went back to engine oil. This was at 184k miles, the car has since been sold on, last time I saw it was a year and a half ago at 260k and it's still chugging along nicely.
Can't tell me it does nothing, because through experimentation it did.
Thinner oils in general can help dislodge some stuff in an engine. That's probably where some of the ATF cleaning stories come from.
My hands are only clean after I spend time working in ATF. There is no question that it dislodges filth from the inside of an engine.
I'm on Pete's side here.
As far as engine oils dissolving sludge... it depends. A common issue when changing an older car over to synthetic oils is that. Every one of our cars I've moved over to Wally World Synthetic always looks like poo and burns about a quart in 3k miles when it has never burned any oil ever before. Change it at that early interval (for us, 3k is really early) and it's good to go. You can usually see the varnish on the dipstick slowly disappear as well.
Now, this is anectdotal evidence, but professionally different oils have different ad packs that do different things. Some conventional oils coke up easier than others causing more varnish etc.
I rarely flush, simply because I'm pretty religious about my maintenance intervals. I had a Caddy 390 that went 560k without a flush (that I know of) and had zero sludge under the valve covers when I did gaskets. When I DO flush, I use a quart of diesel.
If you were to do back to back tests... as in, if you had two identically dirty sludgy engines. Run one with an ATF flush, and one with, let's say a straight 0w20 engine oil flush, the 0W20 would dislodge the same or more sludge than the ATF. The ATF may get some sludge out, but not because it has more detergent. The difference is where the sludge ends up. With ATF, it ends up in the filter where you can see it. With engine oil, it stays suspended in the oil and comes out the drain hole.
Panther, you are correct about detergents and suspension. It's not like soap, it has to do with keeping contaminants in suspension, which only lends credence to what I was saying. ATF doesn't need nearly as many detergents as engine oil. A transmission offers the potential for tiny amounts of condensation, scrubbed-off particulates (paper) from the clutches, and metal shavings. Those things shouldn't be in suspension. You want them to fall into the pan. The filter on an automatic transmission isn't much of a filter, more of a screen that is there to protect the pump and prevent clogs in the nooks and crannies of the hydraulic circuits.
I would contend that the filter junk in Pete's pictures could simply be that the ATF couldn't hold the solids in suspension and it's just bigger, more visible chunks, but given HOW oils and detergents carry the junk doesn't necessarily change the amount of sludge and deposits there are in an engine. I would bet that if you did the test with ATF and 20w I mentioned above and then found some way of measuring the amount of junk that came out via the oil vs the filter, you would see about the same mass of junk in both. It's just that the ATF leaves it in the filter and the oil hangs on to it.
My point was not necessarily to say that ATF offers zero benefit. Maybe it does clean a bit of junk out, but the only scientific reason it could do that is because of lower viscosity which can be accomplished with wiser choices... like some 20w engine oil. My point was that the whole myth was started because mechanics would open up a transmission at 50k and see this beautiful red fluid and assume it was because ATF is this amazing cleaning fluid... so they put it in an engine and the filter came out yucky, so it must have more detergents. The truth is, transmissions see small amounts of ground up/burnt paper. Engine oil sees hundreds of complex carbon, hydrogen, oxygen, and nitrogen compounds as a result of blow-by. So the myth that transmissions look cleaner inside than engines because ATF is wonderful at cleaning things is a myth.
I'm simply saying that ATF may do something but not much, and it's not the best solvent for the job.
bobzilla said:As far as engine oils dissolving sludge... it depends. A common issue when changing an older car over to synthetic oils is that. Every one of our cars I've moved over to Wally World Synthetic always looks like poo and burns about a quart in 3k miles when it has never burned any oil ever before. Change it at that early interval (for us, 3k is really early) and it's good to go. You can usually see the varnish on the dipstick slowly disappear as well.
Now, this is anectdotal evidence, but professionally different oils have different ad packs that do different things. Some conventional oils coke up easier than others causing more varnish etc.
I agree, and it has a valid reason. Mineral oil becomes engine oil by using physical and chemical means of removing all the stuff that isn't engine oil. You start with crude oil which contains hydrocarbons ranging from propane (c1-c4) all the way up to asphalt (c70). Lubricating oils fall in the C40-50 range. Since the primary means of extracting lube oil from crude oil is by heating and cracking the molecules, regular mineral oil only gets close. You'll have plenty of other carbon chains left in it as well as other minerals and compounds that it picked up from its life underground. It's like picking the dirt out of your wash water. You can get close, but it will never be pure water by mechanical means. Synthetic oil on the other hand is made by artificially creating carbon compounds in a lab. They physically only make C40-c50 molecules to start with. No dirt, other carbon chains, just pure hydrocarbons.
In this way, synthetic oil is to mineral oil as distilled water is to tap water. Since the synthetic has less stuff already dissolved in it, it can dissolve far more junk. This is the primary reason why most synthetic oils can go for longer periods of time in an engine. It is still collecting the same junk, but there is more "space" for solutes in the oil.
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