Positive Crankcase Ventilation Valve: Testing and Inspection

Before inspecting the PCV valve, make sure that the hoses are connected properly and are in good condition. Also check that the oil pan and rocker cover gaskets are sealing properly.

PCV Valve
1. Run the engine at normal operating temperature.
2. Disconnect the valve from the rocker cover.

RESULT: A hissing noise should be heard from the valve. If no noise is heard, the PCV valve or hose is plugged.

3. Remove the PCV valve from the engine.
a. Blow air into the rocker cover side of the valve.

RESULT: Air should pass freely.

b. Blow air into the air cleaner side of the valve.

RESULT: Air should not pass through the valve.

4. Re-install the PCV valve and remove the oil filler cap.

RESULT: A small vacuum should be felt at the oil filler hole.