THE BASIC OPERATION OF A PCV VALVE
(POSITIVE CRANKCASE VENTILATION)
A PCV valve is one of the first pollution control devices. It allows crankcase fumes to be burned in the combustion process. Engine vacuum pulls airborne pollutants from the engine valve cover to the carburetor or fuel injection system through a rubber hose. The PCV valve is a small plastic or metal cylinder housing with a valve & spring inside. When the engine is running, engine vacuum draws engine fumes to the air intake system. Engine vacuum is greatest at an idle.
A PCV valve that sticks could cause an engine to:
1. idle rough
2. have poor acceleration
3. form sludge
4. cause poor fuel economy
Check vehicle manufacturer for service intervals.