2004 C70 PCV Crank pressure

[gkrogman]

I have a 2004 c70 2.3 turbo. 200k miles. I noticed some oil on the top of the engine near the oil cap. Figured maybe pcv clogged. I did the glove trick and at idle it sucked in then at about 1500rpm it blew out. My compression seems to be over 100 psi (tested with a gauge I had around) so I don’t think its blow by. When I blow into the tube from the top of the engine to the oil separator box it seems clear.
Any ideas?

[Ozark Lee]

The tube from the top of the engine is rarely the problem in the PCV system. Most of the trouble is from the bottom of the oil trap into the sump or in the line from the oil trap to the intake through the PTC valve. If the compression really is only 100 PSI then it is very low, by about 1/2. The compression gauges are all over the place in terms of quality and warm vs cold engine, wet vs dry (a bit of oil added to the cylinders), and making sure the throttle is open can make huge differences in the measurement though so it may or may not be low. At 100 PSI across the board the engine will barely run if it will run at all.

The behavior you describe is indeed typical of a clogged PCV although I don't know first hand how the glove test works at higher RPMs.

...Lee

[gkrogman]

I do have a leak down tester and will try that this weekend.

[gkrogman]

Found the problem. I guess my breather box was clogged. It always burned oil and oil would leak out of the filler cap even with new seals. With over 200k on it I thought that was normal. I did not want to take the intake off to change the box. So I heated up the engine, and poured ¼ cup of engine medic in the hose going to the top of the breather box. Did this every 15 min and started and ran the engine each time. After half of the bottle was in, I poured the rest in the engine, idled for a half hour then changed the oil. No more thick smoke and no more oil coming out the oil fill. By the way I also had an “engine running rich at idle” code and that is gone as well.