Nissan Pick-ups and Pathfinder 1989-1995

PCV Valve

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See Figures 1, 2, 3 and 4

The PCV valve regulates crankcase ventilation during various engine operating conditions. At high vacuum (idle speed and partial load range) it will open slightly, and at low vacuum (full throttle) it will open fully. This causes vapor to be removed from the crankcase by the engine vacuum and then be sucked into the combustion chamber where it is dissipated.

The PCV system will not function properly unless the oil filler cap is tightly sealed. Check the gasket on the cap and be certain it is not leaking. Replace the cap and/or gasket, if necessary, to ensure proper sealing.

TESTING



  1. Check the ventilation hoses and lines for leaks or clogging. Clean or replace as necessary.
  2.  
  3. With the engine running at idle, locate the PCV valve in the cylinder head cover or intake manifold and remove the ventilation hose from the valve; a strong hissing sound should be heard as air passes through the valve.
  4.  
  5. With the engine still idling, place your finger over the valve; a strong vacuum should be felt.
  6.  
  7. If the PCV valve failed either of the preceding two checks (and the ventilation hose is not clogged or broken), the valve will require replacement.
  8.  

REMOVAL & INSTALLATION



See Figures 5, 6 and 7

  1. If not already done, detach the ventilation hose from the PCV valve.
  2.  
  3. Remove the PCV valve. If its base is threaded, unscrew the valve; otherwise, simply pull the valve from its retaining grommet.
  4.  

To install:
  1. Depending on the type of valve, either screw in the replacement PCV valve or push it into its retaining grommet.
  2.  
  3. Slide the ventilation hose onto the end of the PCV valve.
  4.  

For further information on the PCV system, please refer toChapter 4of this manual.



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Fig. Fig. 1: PCV valve location-Z24i engine



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Fig. Fig. 2: PCV valve location-VG30i engine



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Fig. Fig. 3: PCV valve location-KA24E engine



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Fig. Fig. 4: PCV valve location-VG30E engine



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Fig. Fig. 5: Checking the PCV valve-Z24i engine



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Fig. Fig. 6: Checking the PCV valve-VG30i engine



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Fig. Fig. 7: Checking the PCV valve-KA24E and VG30E engines

 
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