Catera V6-3.0L VIN R (1997)
Positive Crankcase Ventilation: Description and Operation
Description
A closed crankcase ventilation system provides a more complete scavenging of crankcase vapors. Fresh air from the engine air induction system is
supplied to the crankcase, mixed with blow-by gases and then passed through the Positive Crankcase Ventilation (PCV) housing into the intake
manifold.
Operation
The primary control is through the Positive Crankcase Ventilation housing which meters the flow at a rate depending on the manifold vacuum. In order
to maintain the idle quality, the PCV housing restricts the flow when the intake manifold vacuum is high. If abnormal operating conditions arise, the
system is designed to allow excessive amounts of blow-by gases to back flow through the crankcase vent tube into the engine air inlet to be consumed by
