Positive Crankcase Ventilation: Description and Operation

PCV Valve:

PURPOSE
The Positive Crankcase Ventilation (PCV) system vents harmful blow-by fumes from the engine crankcase into the intake manifold for burning with the fuel and air mixture.

OPERATION
The PCV valve varies the amount of blow-by gases fed to the intake manifold in direct relation to engine demand and serves to prevent combustion backfiring into the crankcase. Thus, the benefits from the PCV system include the ability to:

^ Maximize the oil cleanliness by venting moisture and corrosion from the crankcase.
^ Protect against crankcase explosions.
^ Automatically regulate the ventilation of crankcase blow-by gases to the intake manifold in direct relation to engine operating conditions.

The amount of blow-by gas allowed into the intake manifold from the crankcase is controlled by the PCV valve. The PCV valve acts as a one-way valve, it does not allow anything from the intake manifold to pass into the crankcase. The PCV valve is located on top of the valve cover.