Crankcase Ventilation System Description: General Description
WARNING: This page is about a different car, the 2003 Pontiac Montana, 2003 Oldsmobile Silhouette, and 2003 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
A crankcase ventilation system is used to consume crankcase vapors in the combustion process instead of venting them to atmosphere. Fresh air from the throttle body is supplied to the crankcase, mixed with blow by gases and then passed through a PCV valve into the intake manifold.