Positive Crankcase Ventilation: Testing and Inspection

Checking Crankcase Pressure:

PCV Valve Location:

FUNCTIONAL CHECK
If any 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 cam 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 valve, check for plugged hoses, 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 a 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 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 cause and correct to ensure that system will function as intended.

RESULTS OF INCORRECT OPERATION
A plugged PCV valve or hose may cause:
^ Oil Leaks
^ Sludge in engine

A leaking or faulty valve or hose would cause:
^ Rough idle
^ Stalling
^ High idle speed
^ PCM trouble codes


REPLACEMENT
An engine which is operated without any crankcase ventilation can be damaged. Therefore, it is important to replace the PCV valve when the valve fails a diagnostic check or does not rattle. Inspect the hoses and clamps and replace if they are deteriorated.