Pressure in the crankcase?? Common Problem?

[masitaly17]

Hello,

I am doing some research for a buddy of mine with a 2003 G35. He had me look at his car for a "noise" towards the left front of the car. I thought it was going to be a belt but ended up being more of a pressure noise than mechanical.

I took the dipstick out and sure enough the crankcase had pressure in it (pressure relief noise when removing dipstick). He picked up a PCV valve and it still has the same noise. A buddy said he vented one of the hoses in the PCV circuit to atmosphere and it went away.

I figured this is likely a common problem with these engines and you guys could share your thoughts. I did a search but it did not yield much.

I am an engine guy but do not know anything about this specific engine.

Your help is apprcieated in advance

[maxnix]

PCV valve?

[Q45tech]

Venting the designed in crankcase pressure throws the MAF voltages for a loop.

The question is how much pressure and does it exceed oem design? Poor ring sealing [bad rings] cause excess pressure.

Normally as compression pressure drops crankcase pressure increases.

Installing new fresh PCV is a good first start.

Now measure each cylinders compression pressure and compare to parameters in FSM.