ATF in the engine like changing to synthetic oil?

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Dec 31, 1969
I have a Jeep Cherokee with the 4 liter engine. It's got 98,000 miles on it, and I'm sure the insides are pretty dirty as the previous owner rarely changed the oil. I cleaned off some pretty big chunks from the inside of the oil filler cap. It's got a stuck lifter, or something in the area of the valves making a tapping noise. I was thinking of running a quart of ATF in the crankcase for a little while at idle to try and clean it out/stop the tapping. Might this be a bad idea? I mean, I know you're not suppost to switch to synthetic oil on a high mileage engine, because it can start to leak. Wouldn't this be kind of the same thing?
ATF won't clean out much if anything at all. New ATF formaulas actuall have less detergents than motor oils. Run an AutoRX treatment. It will do wonders!
The idea of ATF cleaning in the old days had some merit. Sperm whale oil, and some detergents higher than normal motor oil that old ATF used to have indeed would clean OK. Nowadays it makes zero sense to put this effectively 10W oil in, because indeed it has LESS detergents. Sounds like you need a double or triple AutoRX
Best bet would be to run some ARX. If you don't want to do this, then I would recommend this procedure: 1. Go buy some HDEO 15w-40 2. Buy an oversized filter 3. Go drive her around [Cheers!] [ October 23, 2003, 01:05 PM: Message edited by: Jelly ]
Well, whatever I use, might it be a bad idea because it could cause my old engine to leak? BTW - I tried some marvel mystery oil a while ago, didn't help anything.
[Cool] Either the Auto RX or just buy a good but not expensive filter and good but not expensive oil and change it every 2000 miles for a while. That's what I did with the old work van I bought. If it wasn't well cared for previously, I'd flush the antifreeze, run a bunch of Gumout or whatever though it, and change the fuel filter too. Van had a bad off-idle stumble when I got it but it's gone now.
Originally posted by ZmOz: Well, whatever I use, might it be a bad idea because it could cause my old engine to leak? BTW - I tried some marvel mystery oil a while ago, didn't help anything.
Seems like nobody wants to answer your question. You may have some current oil leaks that do not leak because they have sludge build up blocking the leak. If you think about it, if there is sludge blocking a leak - there is also sludge blocking somewhere else inside the engine too - this is not a good thing. Now, this is where AutoRX somes in, it will condition and slightly swell the seals potentially stopping any of these potential leaks. FWIW, I switched to synthetic oil with over 100k on an engine with no leaks at all.
I cannot imagine somebody using automatic transmission fluid in an engine. A bottle of Auto-RX does not cost that much. A bottle of Neutra costs even less. Surely an engine is worth that much money.
This has come up before. Engine oil in the engine and ATF in trans. Putting ATF in your engine will do absolutely nothing to clean it out. Just an old mechanics tale that keeps getting bantered around for many years. Follow the advice given and use the right product.
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