That's the way it's supposed to work.. You're right,, at some point the crankcase pressure will exceed vacuum,, that's where the breather comes in, and vents the excess crankcase pressure/vapors to the air cleaner,, So the motor needs both parts to be a complete system,, the PCV to suck out the vapors at less than WOT,, and the vent to the A/Cleaner for excess pressure.. Didn't we cover this under the "Massive Oil Leak" thread..???
