Sentra Wagon FWD L4-1597cc 1.6L SOHC (E16i) (1988)
Positive Crankcase Ventilation Valve: Testing and Inspection
With engine running at idle, remove ventilation hose from P.C.V. valve; if valve is working properly a hissing noise will be heard as air passes
through it and a strong vacuum should be felt immediately when a finger is placed over valve inlet.