My friend's got a 1995 850 turbo wagon with a serious crankcase pressure problem.
I finally got to take a brief look at it last night while he was swapping on a replacement intake bellows.

-There's substantial oil and vapor coming from the dipstick tube.
-The intake bellows has a lot of oil downstream of PCT valve
-The RMS has not blown-out (yet).
-The turbo itself seems to be in great shape

Sound like a *really* clogged PCV system, eh? That's the difficult part. The entire PCV was only 2 years-old when these symptoms developed.

He also *just* replaced the entire system (again), he cleaned the PCT valve, and checked the oil-trap openings on the lower block for any blockage. Unfortunately the problem has continued and intensified. It's so bad that he put on an oil catch-can to keep the oil spewing all over the engine compartment.

I don't know a whole lot about this car, but the mileage is around 180k. The car was owned by a family member and it was given regular maintenance over its life. The engine was also serviced by a mechanic just before he got the car. I think he said that a burnt valve was replaced, the ECM for the engine was replaced, and the MAF was replaced.


From my observation of the car, I learned the following:

-the air intake system plastic bellows were badly damaged or missing. The fresh-air intake to the airbox is missing entirely. The bellows at the connection to the turbo was broken.

-the oil seems to have been switched from synthetic back to dino. Possibly a heavy-weight oil was put into the block.

-the cooling pipe between the radiator and computer modules is broken/half-missing



I've got some ideas
1) the PCV is clogged internally - possibly from crud inside the engine - maybe from switching the type of oil and dislodging gunk -OR- the prior mechanic dislodged gunk at the oil trap and it went into the block.
This seems likely.

2) The ECM is "wrong" and/or the compromised air intake system is leading to "overcompensation" by the control system - making it run hot, throwing off the timing, or something like that.
Seems unlikley. I'm sure the compromised intake is not helping, but I don't see it as a cause of excess crankcase pressure.

3) Worn-out piston rings leading to excess blow-by that overwhelms the PCV system.
Possibly. At 180K, it shouldn't be anywhere near that bad. Still... oil is definitely being pulled through the PCV into the intake.

4) Something else creating pressure in the block.


Any thoughts?