Chevrolet Equinox Service Manual: Crankcase Ventilation System Description Emissions PCV

A crankcase ventilation system is used to consume crankcasevapors created during the combustion process instead of ventingthem to the atmosphere.

Fresh air is supplied through a filter to the crankcase, thecrankcase mixes the fresh air with the blow-by gases and thenpassed through a positive crankcase ventilation-(PCV)orificed tube into the intake manifold.

The PCV orificed tube restricts the flow rate of the blow-bygases using an orifice-(1) located at the end of thetube. If abnormal operating conditions arise, the system isdesigned to allow excessive amounts of blow-by gases to back flowthrough the crankcase vent tube into the throttle body in order tobe consumed by normal combustion.