Functional Check of PCV Valve

It an engine is idling rough, check for a clogged PCV valve. Replace it required. Use the following procedure:
1. Remove PCV valve from the intake manifold.
2. Shake the valve and listen for the rattle of a needle inside the valve.
3. If the valve does not rattle, replace the valve.

With this system, any blow-by in excess of the system capacity, from a badly worn engine, sustained heavy load, etc. is exhausted into the intake manifold and is drawn into the engine.

Proper operation of the crankcase ventilation system is dependent upon a sealed engine. If oil slugging or dilution is noted, and the crankcase ventilation system is functioning properly, check the engine for possible cause and correct to ensure that the system will function as intended.