Positive Crankcase Ventilation: Testing and Inspection

Crankcase Ventilation System Inspection/Diagnosis

Crankcase Ventilation (CV) System Inspection

* Test for vacuum while the engine is running at the foul air PCV tube where it connects to the RH camshaft cover PCV orifice fitting. There should be manifold vacuum present at the tube connector. If there is no vacuum, inspect for a plugged tube or connector, or a plugged intake manifold PCV fitting.
* Plug the end of the foul air PCV tube while the engine is running. Inspect the tube for any areas that collapse when the end of the hose is blocked. Replace the PCV tube if it collapses when blocked.
* If oil has accumulated in the intake air duct, inspect for the following conditions:

- Plugged PCV orifice in the RH camshaft cover PCV fitting
- Plugged or restricted PCV fitting on the intake manifold
- Excessive crankcase pressure or blow-by, refer to Oil Consumption Diagnosis (Component Tests and General Diagnostics) .

* Additional items to inspect:

- Plugged or leaking fresh air PCV tube
- Missing or damaged PCV tube connectors
- Inspect the cam covers, the oil pan gasket, and other sealing areas for leaks.




Results of Incorrect Operation

* A plugged PCV orifice fitting or PCV foul air tube may contribute to the following conditions:

- A rough idle
- Stalling or a slow idle speed
- Oil leaks
- Oil accumulation in the intake air duct
- Sludge in the engine

* A leaking PCV fresh air tube may contribute to the following conditions:

- A rough idle
- Stalling
- Unstable idle speed