Positive Crankcase Ventilation: Testing and Inspection

Crankcase Ventilation System:

FUNCTIONAL CHECK OF CRANKCASE VENTILATION VALVE

If an engine is idling rough, check for a clogged crankcase ventilation valve or plugged hose replace as required. Use the following procedure:

1. Remove valve retainer plug from rocker arm cover
2. Remove valve from rocker cover
3. Install valve in vacuum hose
4. Run the engine at idle.
5. Place your thumb over end of valve to check for vacuum. If there is no vacuum at valve, check For plugged hoses in manifold port or valve. Replace plugged or deteriorated hoses.
6. Turn "OFF" the engine and remove valve. Shake valve and listen For the rattle of needle inside the valve. If valve does not rattle, replace 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 air cleaner and drawn into the engine.

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