Positive Crankcase Ventilation Valve: Testing and Inspection

PCV VALVE
Operational Inspection

Caution: Disconnecting the valve while the engine coolant is warm, over 20° C (68°F), can let the engine inhale enough air through the valve to cause difficult starting.
1. Verify that the engine coolant temperature is below 20°C (68° F).
2. Start the engine and let it idle.
3. Disconnect the PCV valve from the cylinder head cover.




4. Block the valve opening by hand and verify that vacuum is felt.
5. If not, check the PCV valve for clogging and damage. If the hose is OK, replace the PCV valve.