I went to replace my PCV today and noticed it was hollowed out. The previous owner capped the intake manifold side and ran the vent hose down the side of the car to ambient air - which I know many do. But I was surprised when I removed the old valve that it was completely hollowed out. Is this something others have done to just have the entire system open air?! It seemed a bit odd to me. The car has been running great...

Old on left, new on right.

 

I don't know, but for some reason I'm now left with a vision of a cartoon bird in my mind.

My apologies, hopefully someone with an answer that is actually helpful will be along shortly.

 

If you are running the PCV to open air instead of the intake manifold source then yes it's better to remove the check valve.

 

yeah they relied on pressure within the upper valvecover to push out air, so the check valve had to be hollowed out or you would get excessive crank pressure. Still always better to evacuate crankcase vapours under vacuum rather than running to open air, just get an oil catch can rather than running to open air.

 

Ah-makes sense. Thanks guys!