Changing dirty oil - should I run a couple of quarts of clean through it?

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Dec 31, 1969
I'm going to be changing the oil again for the 3rd time in about 1000 miles...because the inside of my engine is DIRTY. Right now I'm only using cheap dino oil because I'm changing it so often and a good bit of it ends up on the road from my rear main leak. After I drain out all this dirty oil, might it be a good idea to pour a quart of clean oil in and drain it out again? Or maybe ATF, since it is thinner? Or is that just a waste of my time?
Maybe the inside of your engine is dirty because of the cheap dino oil! Agreed that Auto-RX is a good idea; it may help with your rear main seal leak as it cleans. You might also try one of the high mileage oils to help with your seal issue. Pennzoil High Mileage has gotten some good press on this site.
As a rule, "cheap dino oils" will not clean the inside of the engine. You need an oil that cleans such as Redline, Amsoil, and maybe GC to be able to do this with oil alone.

Better yet, and AutoRX treatment may clean your engine and seal the leak at the same time.

Idea on extended drains here - if it is leaking as bad as you make it sound, just keep toping off the oil, change the filter at the recommended time and you'll never need the drain the oil again.

Originally posted by GROUCHO MARX:
I guess you guys didn't see the exchange between Frank (A-RX) and ZMOZ?


Actually your only hope is the AutoRX. If you don't want to use the product, then your only other option is to have the rear main seal replaced (assuming that's where it is leaking from). No amounts of dino changes & ATF fluid is going to make this stop.

Stop wasting your money on oil changes, & fix the engine. . .

[ December 01, 2003, 08:51 PM: Message edited by: Randy ]
I plan on changing the rear main and valve cover soon, and at that point nearly every seal in the engine will have been replaced. I will then switch to synthetic...which will do all the cleaning I need. Until then, does anybody have an comments on my original question?

In this thread a few folks have bashed "dino" oils, but in fact, it appears that in dirtying themselves in just a few hundred miles, they're doing exactly what they're supposed to do -- clean the engine. I don't believe the cheap cleaners/flushes (Rislone, CD2, Marvel Mystery, Valvoline 5 minute flush, etc.) are useless, in spite of their simplistic formulations (kerosene, mineral oil, naphtha, etc.). But using anything resembling a "shock" treatment may be dangerous if your engine is as cruded-up as you suggest -- you could potentially dislodge stuff which could cause you circulation problems. So a slower approach might be appropriate, such as AutoRX, "diesel" motor oil, etc. Or if your current method is working well, what the heck, stick with it, especially if you're using 69 cent after-rebate oil. Make sure to regularly change your filter through this process as well.

As for pouring a quart of oil through the engine at the end of an oil change, that would certainly be a waste for several reasons, but notably, the oil would drain only through the oil channels directly below the oil cap, leaving most of the oil system untouched (not that this would accomplish anything anyway).

Originally posted by ZmOz:
-*-* After I drain out all this dirty oil, might it be a good idea to pour a quart of clean oil in and drain it out again? Or maybe ATF, since it is thinner? Or is that just a waste of my time?

Worry about cleaning things up AFTER the seal is fixed. This is doing more harm than the crud in the engine....
After the seal is fixed.... You may want to do a light flush for a few miles or a few hundred or a very short OCI... then worry about clean up...

ps --how many miles?
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