View Full Version : ls1 valve cover breathers...suck or push air out?

awd-rwd racer
06-19-2012, 10:28 PM
the breathers on the ls1 valve cover, are they supposed to suck air in or push air out?

06-20-2012, 08:58 AM
They suck in, that's why there's a filter so it's fresh but filtered air.

The PCV is what pushes vapors out of the crankcase, or better yet it gets pulled out by the vacuum of the manifold.

06-20-2012, 02:40 PM
if you run a properly plumbed PCV system the breather is just hurting you more than anything. properly plumbed means it goes from the valve covers, into a pcv valve, and then to an oil catch can and back to the intake.