Positive Crankcase Ventilation: Testing and Inspection

PCV SYSTEM TEST

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 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 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 causes (i.e. missing oil cap). Correct to insure that system will function as intended.


A plugged PCV valve or hose may cause:

^ Rough idle.

^ Stalling or slow idle speed.

^ Oil leaks.

^ Oil in air cleaner.

^ Sludge in engine.

A leaking valve or hose could cause:

^ Rough idle.

^ Stalling.

^ High idle speed.

An engine which is operated without any crankcase ventilation can be damaged. Therefore, it is important to replace the PCV valve and air cleaner breather at proper maintenance intervals, see "MAINTENANCE PROCEDURES".