PCV Valve

PCV Valve:

In order to maintain idle quality, the PCV valve restricts the flow of blowby gas whenever intake manifold vacuum is high. Abnormally high crankcase pressure may cause the blowby gases to flow through the crankcase vent tube and into the air cleaner. The blowby gases are then drawn into the intake system and consumed in the normal combustion process.

PCV Valve Operation:

The relationship between the flow of blowby gas and engine manifold vacuum is charted in the above table.