Just completed front cam seals,timing belt complete replacement of all PCV system parts. I have found that the engine develops vacuum build up in the crankcase. Enough that it generates a pulsing squeal like a rubbing belt emanating from near the oil pour cap. If I remove the oil cap or oil level stick the noise goes away after sucking in air. Put the cap and dip stick back in and the noise comes back very quickly. What could this be?? The engine runs and drives fine otherwise but I think the heavy vacuum will cause other issues if not sorted out. 153k miles.
looking forward to some ideas of what is going on here.
Thanks, Alex

 

Hello
The squealing sound is most likely due to a faulty diaphragm, 7€ part, easily replaceable : you will find videos on YouTube of how to perform the replacement. Parts easily found on various sites. Hope that helps, all the best

 

Did you replace the metered /check valve banjo bolt? Or replace it with one without a check valve? Pretty sure that's the only place manifold vacuum is tied to the pcv system. (on the bottom of the intake manifold)

Check this post - https://www.matthewsvolvosite.com/fo...ic.php?t=97315

 

Chalk one up for not inspecting the new parts you install. I bought new parts from a reputable dealer but in this case there were very nice and answered all my support needs. It ended up that one of the aluminum tubes that draws metered air and brings it around to the PVC oil settling reservoir was plugged was plugged during manufacturing with the same foam they use to insulate it as it wraps around from front to back of the engine. It was difficult to find the flaw because the part comes as an assembled unit with formed rubber ends on it. This made it impossible to see the defect without disassembling the new part.
The car fired up perfectly after removing about an inch of hard injected foam from the end of the tube. Too bad working on the PVC stuff is buried so deep on this engine. This took many hours of trouble shooting to resolve.