For 1990-2009 cars

### Results of Incorrect Operation

• | A plugged positive crankcase ventilation (PCV) orifice or hose may cause the following conditions:

- | Rough idle

- | Stalling or slow idle speed

- | Oil leaks

- | Oil in the air cleaner

- | Sludge in the engine

• | A leaking PCV orifice or hose may cause the following conditions:

- | Rough idle

- | Stalling

- | High idle speed

### Functional Check

With these systems, any blow-by in excess of the system capacity, from a badly worn engine, sustained heavy load, etc., is exhausted into the air cleaner and is drawn into the engine.

Proper operation of the crankcase ventilation system depends upon a sealed engine. If oil slugging or dilution is noted and the crankcase ventilation system is functioning properly, check the engine for a possible cause. Correct any problems.

If an engine is idling rough, inspect for a clogged PCV orifice, a dirty vent filter, air cleaner element, or plugged hose. Replace as required. Use the following procedure:

• | Remove the PCV hose from the cylinder head cover.

• | Operate the engine at idle.

• | Place your thumb over the end of the hose in order to check for a vacuum. If there is no vacuum at the hose, inspect for the following items:

- | Plugged hoses

- | The manifold port

• | Turn OFF the engine.

• | Inspect the PCV orifice in the cylinder head cover for debris or blockage.