Oil Overfill Produces Positive Crankcase Pressure??

andyleonard · Post by **andyleonard** » 06 Jul 2022, 01:09

OK. My son had a 90K complete-head-rebuild on a 97 850; all vacuum stuff, codes, new PCV, hoses, belts, everything, done at head-off. Car was excellent, CA smogged, no codes, no issues. He drove to Seattle from L.A., no issues. Drove around Seattle for a year, no issues. In prep for a Seattle-L.A. run it got overfilled by - we're guessing - 1/2 quart due to a sloped driveway.

Car ran fine Seattle to L.A., BUT oil dripped from full plug well - leaking from new oil fill cap - onto exhaust manifold and SMOKED. Oil overfill was corrected, head cleaned up and no more smoke, BUT now crankcase has positive pressure.

Question: Is the new PCV stuff damaged? Can something be drained? Did a hose blow off something?

I'm on an island, he's in Boston, car's in L.A.

Thoughts? And thank you.

Post by **abscate** » 06 Jul 2022, 01:35

An overfill won’t cause crankcase pressure. Probably a hose loose somewhere in the system, or you Have reached the six month end of life of aftermarket rubber.

Post by **erikv11** » 06 Jul 2022, 08:04

abscate wrote: ↑06 Jul 2022, 01:35 An overfill won’t cause crankcase pressure. Probably a hose loose somewhere in the system, or you Have reached the six month end of life of aftermarket rubber.

Such wisdom. What he said.