Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Positive Crankcase Ventilation: Testing and Inspection

Positive Crankcase Ventilation System:






PCV VALVE TESTING

1. Remove PCV valve from valve cover but leave attached to hose.
2. Start engine and run at idle.
3. Check for vacuum at the valve by placing a finger over the open end. Strong vacuum should be present.
4. If there is no vacuum, stop engine and check for plugged hose, manifold port or PCV valve.
5. Inspect PCV valve metered orifice and clean or replace valve as required. Shake valve and listen for rattle. Replace valve if it does not rattle. Replace hose if defective.
6. Clean manifold port if needed.