Positive Crankcase Ventilation: Testing and Inspection
Crankcase Ventilation System Inspection/DiagnosisCrankcase Ventilation (CV) System Inspection
^ Test for vacuum at the positive crankcase ventilation (PCV) dirty air hose where it connects to the vacuum orifice tube in the engine valley cover. There should be a manifold vacuum present at the hose. If there is no vacuum, inspect for a plugged hose, leaking hose or a plugged intake manifold passage.
^ If oil has accumulated in the intake, inspect for the following conditions:
- Plugged vacuum orifice tube in the engine valley cover
- Plugged, restricted, or leaking PCV dirty air hose
- Plugged or restricted intake manifold passage
- Excessive crankcase pressure or blow-by
Additional items to inspect:
^ Plugged or restricted PCV fresh air hose
^ Inspect the valve rocker arm cover, the oil pan, engine front cover, and other sealing areas for leaks
Results of Incorrect Operation
A plugged crankcase ventilation system may contribute to the following conditions:
^ A rough idle
^ Stalling or a slow idle speed
^ Oil leaks
^ Oil accumulation in the intake manifold
^ Sludge in the engine
A leaking hose may contribute to the following conditions:
^ A rough idle
^ Stalling
^ Unstable idle speed
The crankcase ventilation system has no serviceable components so no maintenance of the system is required.