I think I started a monster...I was just checking, because the ATF works really well for Volvos, but that is a different beast all together.

interesting read

http://au.geocities.com/ozbrick850/atf-fundaments.html

One point I got is if there are contaminants in the oil, they cause damage to things such as surfaces between seals and crank. So flushing a very dirty engine and loosening a bunch of crap that ciurculates through the engine maybe enough to damage an old hardened or cracked seal and cause it to leak. I think the disolving sludge theory in my previous post is equally culpable.

[QUOTE=Cking1975;3883621]I have done an engine flush on my high mileage Saabs and Volvos. QUOTE]

So, I take it you've fixed the infamous crankcase ventilation/sludge issue on your 9-5?

That was the point of the discussion....stated in the Clark manual, if you have excessive lifter noise on a 944, there could be a block in the oil pickup, not allowing the correct oil pressure to the top of the motor...Personally, if I had this problem, I would use a detergent to clean the motor.

I was talking about your Saab, I just sold my 9-5 back to GM. There are lots of discussions on Saab Central forum about sludge. All engines develope sludge, Saab got a bad rap because they did a recall of the vent tube to reduce sludge.

I've had very good succes on a couple of Mazdas that I've owned adding 1 qt kerosene in the oil and idling for 1/2 hr before draining and completing the oil change. Diesel fuel is probably just as good. Hydraulic lifters on older Mazdas often clack, and this treatment has fixed that as well as cleaned out sludge. The car with sludge had the thermostat stuck open and ran cold for a long time. I attribute the sludge problem to that.

Please tell me this isn't true.

Seafoam is a solvent. It has no lubricating qualities at all. The benefits of removing any sludge are more than offset by the damage you certainly did to your engine.

FWIW I drain one quart of oil prior to a change, add one quart of ATF, run until warm, then drain. The detergents in the ATF are superior to those in motor oil (especially old motor oil) and it definitely results in a lot of the internal crud getting loosened up and drained out. Because the viscosity of the ATF is thinner than most oils, I don't recommend using more than one quart in this manner. The important thing is that ATF IS oil - it has lubricating qualities and is not a solvent like seafoam or that gunk crap in the silver can or any of the other "pre oil change" garbage that's sold at Pep Boys.

Seafoam is fantastic for removing carbon deposits although there's some debate as to whether even this (sucking it in through a vacuum line and using it to clean combustion chambers) is dangerous. The carbon dust/deposits do have to go somewhere, and on their way "out the door" so to speak, they may just tear up cylinders/rings/pistons/valves a bit. Carbon is pretty hard stuff (diamonds are a matrix of carbon atoms). Use at your own peril.

Anyway the point is I do NOT recommend any sort of solvent in one's oil - especially for "hundreds of miles". Doing so is a sure way to quicken your way to an expensive rebuild of the engine. The ATF thing actually does appear to work, but again, I wouldn't drive around with ATF in my engine - use it for its detergent value to loosen up the crap, then drain. And just change your oil regularly ya' cheapskates! ;)

i did the idle to operating temp with one qt of atf then drain without any problems.

a lot of not normal oil change black stuff came out in the process..