Positive Crankcase Ventilation: Description and Operation

Typical PCV Air Flow Diagram:

PURPOSE
The Positive Crankcase Ventilation (PCV) system cycles crankcase gases back through the engine where they are burned.

OPERATION
The PCV valve:
- regulates the amount of ventilating air and blow-by fuel vapor to the intake manifold.
- prevents backfire from traveling into the crankcase.
- is mounted in a vertical position.