System Testing

On gasoline engines with engine idling, remove PCV valve from valve cover and place finger over valve inlet. A strong vacuum should be felt. Turn ignition key off and remove PCV valve from valve cover. Blow into threaded end of PCV valve. If air will not flow, remove PCV and hose and clean with appropriate solvent to remove obstruction. Retest after cleaning.

On diesel engines, check breather hose and valve cover inlet and outlet pipes for clogging and leaks.