PCV Valve Function Check

GENERAL INFORMATION

Positive Crankcase Ventilation (PCV) Valve (Cutaway)

1. VALVE PIN.

If the engine idles roughly or unsteadily, check the condition of the PCV valve and ventilation hose.

The cause may be a blockage in the PCV valve or hose. If necessary, replace the faulty parts following the instructions below.

1) Remove the PCV valve from the intake manifold.

2) Start the engine and let it idle.

3) Cover the PCV valve opening with your finger to check for vacuum. If there is no vacuum,

check the hoses and the intake manifold opening for blockage, and check the valve. Replace faulty parts.

4) Turn the engine off and remove the PCV valve. Shake the valve. A rattling sound from the moving valve pin should be heard.

If no rattling is heard, replace the PCV valve. Sometimes, for example with severe cylinder and piston ring wear, or during prolonged high-load engine operation, the PCV system capacity becomes insufficient to pass all

crankcase gases into the intake manifold. In these cases, some crankcase gases

are routed to the air cleaner and then burned in the engine cylinders.

Normal PCV system operation depends on the condition of the engine seals. If sludge has formed in the engine oil or the oil has become thinner, but the PCV system operates normally,

inspect the engine itself and correct any faults found.

Operating the engine without crankcase ventilation may cause engine damage.

Therefore, it is important to replace a faulty PCV valve in time and periodically replace the

air filter element (or separator, if equipped).

Periodically check the condition of the ventilation hoses and their clamps, and replace defective parts.