Crank case is neutral the vacuum that is used to vent to the PCV system comes from from the intake system. If you open the oil cap or pull the dip stick while the engine is running it will not be pulling vacuum or loaded with pressure. If it is then you have a issue with your engine!The question was is the crankcase under a vacuum or pressure at idle?
The reason I ask is this may be useful for people to determine if the crankcase venting and PCV valve are function properly.
I expect a small vacuum in the crankcase, but just curious what others have found in real world experience. Say cracking the oil fill cap? or checking at the dipstick tube.