Positive Crankcase Ventilation: Testing and Inspection

DIAGNOSIS:

1. Unstable idle; frequent stalling.
a. PCV valve plugged or stuck. Replace valve.
2. Oil in air cleaner.
a. PCV system plugged. Replace valve.

TESTING:

1. Disconnect PCV hose at breather hose.
2. With engine running at idle, place thumb over end of disconnected PCV hose to check for vacuum.
3. If no vacuum is felt, check for clogged hose or valve. Replace as necessary.
4. Stop engine and connect new hose to PCV valve. Blow air through hose to verify that air flows with difficulty from cylinder head side to intake manifold side.
5. If air flows easily, valve is stuck and must be replaced. Wrap threads of new valve with sealing tape before installing.
6. Connect PCV valve hose securely.