kbb6644

I have a 1985.5 944 NA with 345K miles on the original motor. I have discovered motor oil in the bottom of my air cleaner tray underneath the air cleaner filter element. The amount is about a couple of ounces. I have followed the oil trail back thru my AFM and thru the hose that connects to my intake manifold. I took off my intake and also found it there too. Could the Oil be coming from my Oil/air separator? Is the Oil/air separator bad? When I refill oil, I do it on a level surface and fill it to the 2nd mark on my dipstick? Am I overfilling? I've cleaned it all up once and put it back together to find that I had to reset my idle back to 900 RPM (started to idle too high). After running it for a couple of weeks I found the car started to idle much lower than 900 & upon investigation again, found oil back in the air cleaner again!! Any suggestions from anyone? I have replaced the Idle control valve.

ZRDeuce

Did you replace the AOS seals? They are rubber and will shrink over time. I have the same problem and am about to tear it apart.

Do a search of this forum for Air Oil Separator and you will find more info.

JohnKoaWood

AOS seals wont cause this...

Perform an engine leakdown check, and I am willing to bet you have ring leakage... at 345K it is old and could deffinitely use rebuild...

FWIW AOS seals cause leakage on the side of the engine, not into the air filter.. oil in the air filter is an artifact of oil aspiration through the AOS and being blown out of the block by the block being pressurized by ring blowby...

you can try changing oil types, or viscosities to try to cut down the amount of oil being blown out, but the only real way to get totally rid of it is a rebuild...

FRporscheman

I'd tend to agree with JohnKoaWood, it sounds like ring leakage aka blowby. Typical high-mileage problem. You should do a compression and leakdown test, and those are good things to do anyway with that mileage. What type and viscosity of oil do you use?

BTW... 345k miles?!?!?! You're a stud dude. I thought I was cool with my 235k miles on my 968. But even with ONLY 235k miles, my 968 has too much ring blowby which can be smelled by people behind me when I drive. Compression test was low, and leakdown wasn't very good. But, I've never checked my air filter. My oil pressure used to be very low, like 1.2 at hot idle. I went to thick oil and now it's at about 1.8 bar at hot idle. I use castrol 20w-50 dino with a quart of valvoline racing 60w oil.

I have a spare engine in the garage which I will be rebuilding soon. 944 engines are cheap, rebuilding one can get expensive so do your homework, see what you need or don't need, and consider buying a lower mileage used motor.

odurandina

i've been eager to hear about a 300++ K-mile car for a long time.

please add your car to the high mile registry.

https://rennlist.com/forums/924-931-...eage-club.html

kbb6644

Thanks everyone for the info.
Yes ZRDeuce, I have changed the AOS seals. I was hoping you would tell me that my AOS was bad and that it was easy & cheap to fix. Oil was leaking all over the side of the motor & when I changed the seals, that leak went away.
JohnKoaWood & FRPorscheman, I am sad to think that you are probably correct. I want to be in denial about a rebuild. I did do a compression check and the compression in the cylinders ranged from 169 psi to 180. I did not do a leakdown check. I still need to recheck. Do those compression values seem low to you? I was told that it is good if the compression values of all the cylinders are within 10% of each other. I use Castrol 10W40.
ODURANDINA, OMG - Your posting picture stops my scrolling finger on my mouse to a screamin hault!

ZRDeuce

Really a rebuild? I only have 77K miles on mine, but I have only owned it for about 3k of those and put that on in 3 years. I have found that just about anything with rubber on it has had to be replaced. I thought my oil in the air filter was due to bad AOS and valve seals. I was going to pull the head and get that rebuilt, but I guess I should investigate things further and do a leak down test. Compression test was pretty good, I don't remember the numbers but they were all very close.

kbb6644

ZRDeuce, your mileage seems really low to be a rebuild, not unless previous owners were lazy with the maintenance. If you find out anything different in your investigation, please let me know. I am resigned to the fact that I am pretty close to a rebuild but I really wanted to cross 400K with this motor & still may try because the motor still pulls strong.
You are correct about all the rubber. I had to change all the seals, o-rings and gaskets in this motor because every one of them leaked.

JohnKoaWood

Do a leakdown check, this will tell you if the rings are worn causing your crankcase to pressurize and blow oil out into the airbox..

Compression within 10% is OK, I wouldn't call it good... leakdown will tell you the rest of the story..

FWIW my turbo motor only varied by 7, but was getting excessive leakdown on 2 cylinders... it is out and torn apart right now.. full rebuild.