Dexron III ATF in the engine

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I accidentally poured 1/2 qt of Mobil 1 Synthetic Dexron III ATF into my engine thinking it was motor oil.

Is it safe to leave it in there and drive the car? Do I need to do a drain and refill? Or...???
 
Not all that many years ago, it was common to use ATF as an oil additive, especially to clean up a little bit of lifter tick.

Today's oils are much better, and instead of improving it, the ATF probably slightly degraded it. I wouldn't worry about it unless you are going after an ultra long oil change interval. Just get rid of it with the next oil change.
 
i think the small amount of money to replace the oil is worth not putting ur engine in any danger of shortening its life span
 
I accidentally did the same thing in my 99 powerstroke a couple years ago--had a case of oil I had set on the shop floor--wife took a bottle of atf out of the garage when she was cleaning up and stuck it in there thinking it was just random stuff. Bottles were similar and I had 1/2 a quart or so in before I realized it. I left it in and it didn't seem to hurt anything. Of course that is a 15 qt. sump too.
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What engine oil is in you sump and how many quarts? Mileage on oil?
ATF is very light; about 7.5 cSt @ 100C so you've lightened up the oil abit; say 0.25 cSt assuming a 30wt oil and a 5 qt sump. I personally wouldn't worry about it.

Peter
 
4.5qt vs 15qt makes a difference I would think.

I guess I'm gonna drain and refill.
 
I would drain it. My old man tells a story of how he locked up a motor with atf. Oil is cheap! Enginesx are expensive. It might not seem to hurt now, but what about 50k later. Just drop the oil and start with new.
 
Don't worry about it. You could add half a bottle of Synpower Oil Treatment to bring the additives back up (and beyond), but unless you have a small sump, like 3 quart, I don't see a problem.

How do you lock up an engine with ATF unless poured too fast into the intake and hydrolocking a cylinder?
 
I like that story Johnny. Wish I had a company car to experiment on. Always wanted to see what would happen if you ran a tranny filled with only Rislone Engine Treatment.

BTW, the ATF is probably no better or worse than running Rislone and I ran a quart of Rislone every oil change for 175,000 miles and the truck's current owner has it up to 225,000 and running great.
 
Don't expect any cleaning from the ATF [which has minimal detergents [if any] compared to motor oil].
It won't hurt you to have it in until the next change, though.
 
A co-worker brought his older BMW in the shop for some work (BMW dealer?), and he also mentioned about the ticking at start-up. He told me they changed out about a qt of engine oil with ATF. It cured the start-up ticking mostly due to lowering the cold temp. viscosity enough as ATF as little in the way of additives as compared to engine oil. This has been mentioned around here - do a seach on ATF.

The only concern other than additive dilution is how the atf may react with the mosture and other blow-by contaiminents that that would otherwise not be present in a transmission. How about thermal stability also?

Others know a lot more than I on these matters, be this is just some things that pop up in my mind.

By the way, the last I heard of this coworker's BMW is it's still running fine, espcially after replacement of his right rear wheel bearing.
 
20W oil with a red tint will not cause a catastrophic result. Not something I personally would do, but in this case, not a real problem. In fact we have a BITOG member that ran a quart of ATF in a 4 cylinder engine. It did not remove varnish or any other claimed cleaning. He ran it 6K as I remember. This was about 3 years ago and Rugerman, Patman, Joe12, Bob, myself all saw the pictures and explanation. The gent did not want it published.

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I have a friend that cleaned out his Q45 motor by draining the oil, adding ATF and then idling the engine for an hour and then draing and refilling with normal oil.
 
Last year the regional Shell tech rep decided to see what would happen if you ran ATF in your engine. He changed the oil on his company car with all ATF and ran it 3,000 miles. Car never missed a beat and it did not use any ATF. Your 1/2 quart won't hurt anything.
 
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