Subaru Coupes/Sedans/Wagons 1985-1996 Repair Guide

PCV Valve/Filter

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The Positive Crankcase Ventilation (PCV) System recirculates crankcase vapors into the intake stream to be burned during combustion. This system prevents pollution by not allowing the crankcase vapors to escape the engine.

REMOVAL & INSTALLATION



Carbureted Engines

See Figure 1

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Fig. Fig. 1: PCV air filter at the back of the filter housing-carbureted engines

These engines have a PCV air filter attached to the side of the filter housing.

  1. Remove the cover over the air filter element.
  2.  
  3. At the back of the filter housing, mounted vertically, is the PCV air filter.
  4.  
  5. Lift the filter out of the housing.
  6.  

To install:
  1. Slide the filter into the filter housing.
  2.  
  3. Install the air filter cover and wingnuts.
  4.  

Fuel Injected Engines

See Figures 2, 3, 4 and 5

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Fig. Fig. 2: PCV valve attached to the intake manifold-fuel injected models



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Fig. Fig. 3: Disconnect the hose, then use a wrench to loosen the PCV valve at the intake manifold



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Fig. Fig. 4: Remove the PCV valve from the manifold-1991 Legacy shown



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Fig. Fig. 5: Apply Teflon® tape to the PCV valve threads before installing

  1. Disconnect the hose attached to the PCV valve.
  2.  
  3. Use an open-ended wrench or equivalent to loosen the connection between the PCV valve and the intake manifold. Once loosened, remove the PCV valve.
  4.  

To install:
  1. Apply a thin layer of Teflon® tape to the threads of the PCV valve.
  2.  
  3. Install the PCV valve into the intake manifold.
  4.  
  5. Attach the hose to the PCV valve.
  6.  
  7. Start the engine and check for leaks around the connections.
  8.  

SERVICING



  1. Check the PCV ventilation hoses for clogging and leaks. The hoses may be cleaned with compressed air.
  2.  
  3. Check the oil filler cap to insure that the gasket is not damaged and the cap fits firmly on the filler cap end.
  4.  
  5. Disconnect the hose from the PCV valve.
  6.  
  7. Start the engine and place your finger over the top of the PCV valve. Lightly increase the throttle.
  8.  
  9. The valve and system are operating properly when a vacuum is felt. If no vacuum is felt, replace the PCV valve and check the hoses for obstructions.
  10.  
  11. The PCV valve can be checked while off the vehicle by shaking. If a distinct rattling is noticed, the PCV valve is functioning properly.
  12.  

 
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