Positive Crankcase Ventilation: Testing and Inspection

Crankcase Ventilation Valve Flow:

PCV SYSTEM FUNCTIONAL CHECKS
1. Check Positive Crankcase Ventilation ([1][2]PCV) valve for correct application.
2. Engine at normal operating temperature.
3. Block off PCV system fresh air intake passage.
4. Remove engine oil dipstick and install a vacuum gage on dipstick tube.
5. Run engine at 1500 rpm for 30 seconds then read vacuum gage while at 1500 rpm.

INTERPRETING FUNCTIONAL CHECK RESULTS
If vacuum is present, the PCV system is functioning properly. No vacuum indicates the engine may not be sealed and/or is drawing in outside air. Check valve cover, oil pan gasket for leaks. If the vacuum gage registers a pressure or the vacuum gage is pushed out of the dipstick tube, check for the correct PCV valve, a plugged hose or excessive engine blow-by.