Positive Crankcase Ventilation: Testing and Inspection
PCV SYSTEM CHECKIf an engine is idling rough, check for a clogged PCV valve or plugged hose. Replace as required. Use the following procedure:
1. Remove PCV valve from rocker arm cover.
2. Run the engine at idle.
3. Place your thumb over end of valve to check for vacuum. If there is no vacuum at the valve, check for plugged hoses, intake manifold port, or PCV valve. Replace plugged or deteriorated hoses.
4. Turn "OFF" the engine and remove PCV valve. Shake valve and listen for the rattle of check needle inside the valve. If valve does not rattle, replace valve.
With this system, any blow-by in excess of system capacity (from a badly-worn engine, sustained heavy load, etc.) is exhausted into the air cleaner and is drawn into the engine. Proper operation of the PCV system is dependent upon a sealed engine. If oil sludging or dilution is noted, and the PCV system is functioning properly, check engine for possible causes and correct to ensure that system will function as intended.