Avalon 1995-1996

Positive Crankcase Ventilation System

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PCV Valve



Location

Specific to:

Toyota Avalon 1995-1996



Click image to see an enlarged view

Fig. Location of the PCV valve

Operation

Specific to:

Toyota Avalon 1995-1996

The PCV system consists of the breather tube and the PCV valve. The breather tube connects the crankcase to a contained fresh air source such as the air cleaner. Air passes into this tube and into the engine after being filtered through a spark arrestor screen in order to prevent the possibility of an explosion within the engine in the case of a backfire.

Removal & Installation

Specific to:

Toyota Avalon 1995-1996

When replacing a PCV valve you must use the correct one for the engine. Many valves look alike on the outside, but have different mechanical values. Putting the incorrect valve on a vehicle can cause driveability problems.

  1. Pull the PCV valve from the valve cover.
  2.  
  3. Remove the hose from the valve.
  4.  
  5. Check the valve for proper operation. While the valve is removed, the hoses should be checked for splits, kinks and blockages. Check the vacuum port (that the hoses connect to) for any clogging.
  6.  
  7. Inspect the rubber grommet the PCV valve fits into. If it is in any way deteriorated or oil soaked, replace it.
  8.  

To install:

  1. Insert a new valve into the hose.
  2.  
  3. Push the valve into the rubber grommet. Make sure the valve is firmly into place.
  4.  

Testing

Specific to:

Toyota Avalon 1995-1996

Inspect the PCV system hoses and connections at each tune-up and replace any deteriorated hoses. Check the PCV valve at every tune-up and replace it at 30,000 mile (48,000 km) intervals. The PCV system is easily checked with the engine running at normal idle speed (warmed up).

  1. Remove the PCV valve from the valve cover or intake manifold, but leave it connected to its hose.
  2.  
  3. Start the engine.

    Click image to see an enlarged view

    Fig. Blow air from the cylinder head side of the PCV valve, it should flow easily

  4.  
  5. Place your thumb over the end of the valve to check for vacuum. If there is no vacuum, check for plugged hoses or ports. If these are open, the valve is faulty.
  6.  
  7. With the engine OFF , remove the valve completely. Shake it end-to-end, listening for the rattle of the needle inside the valve. If no rattle is heard, the needle is jammed (probably due to oil sludge) and the valve should be replaced.
    CAUTION
    Don't blow directly into the valve; petroleum deposits within the valve can be harmful. Use a separate air source or attach a length of clean hose to the valve.

  8.  
  9. Blow air from the cylinder head side of the PCV valve. It should flow easily. Air should pass with difficulty from the manifold side.

    Click image to see an enlarged view

    Fig. Blow air from the air manifold side, check that the air passes with difficulty



    Click image to see an enlarged view

    Fig. Leaks at gaskets or hose connections can cause the PCV system to malfunction

  10.  

 
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