Frontier XE King Cab 4WD L4-2.4L (KA24DE) (1998)
Positive Crankcase Ventilation Valve: Testing and Inspection
PCV VALVE
With engine running at idle, remove PCV valve from breather separator. A properly working valve makes a hissing noise as air passes through it.
A strong vacuum should be felt immediately when a finger is placed over the valve inlet.