Positive Crankcase Ventilation Valve

(1) Hold the PCV valve with its vacuum applied side down. Using light pressure, depress the thin stick of the PCV valve to 5 - 10 mm.
Release the stick to see if it will return to its original position.
(2) If the stick returns quickly to its original position, the PCV valve is OK. If the stick does not return quickly, clean or replace the PCV valve.