Nissan Frontier, Xterra 1998-05

Valve Covers

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Removal & Installation



2.4L Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the air cleaner assembly.
  6.  
  7. Remove the spark plug wires.
  8.  
  9. Remove the vacuum hoses, electrical harness connectors and harness clamps.
  10.  
  11. If required, remove the power steering belt and position the power steering pump to the side. Remove the idler pulley and bracket.
  12.  
  13. Remove the rocker cover retaining bolts, in the proper sequence.

    Click image to see an enlarged view

    Fig. Valve cover bolt loosening sequence-2.4L engine

  14.  
  15. Remove the rocker cover from the engine.
  16.  

To install:

  1. Be sure to clean the gasket surfaces of the engine and the valve cover.
  2.  
  3. Apply a continuous bead of sealant to the mating surface. Be sure to use the proper grade and type RTV sealant.
  4.  
  5. Torque the retaining bolts to 69-95 inch lbs (8-11 Nm.) and in the proper sequence.

    Click image to see an enlarged view

    Fig. Valve cover bolt tightening sequence-2.4L engine

  6.  

2.5L Engines


Click image to see an enlarged view

Fig. Valve cover and related components-2.5L engine

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Disconnect the PCV hose from the rocker cover. Remove the ignition coil.
  8.  
  9. Remove the PCV valve and O-ring from the rocker cover, as required.
  10.  
  11. Remove the oil filler cap from the rocker cover, as required.
  12.  
  13. Loosen the valve cover retaining bolts in the reverse order shown in the illustration.
  14.  
  15. Remove the valve cover from the engine.
  16.  

To install:

  1. Use a scraper and remove all old gasket material from the cylinder head and camshaft bracket (No. 1).
    NOTE
    Be sure not to scratch the mating surfaces with the scraper when removing the gasket material.

  2.  
  3. Apply genuine RTV silicone sealant or equivalent to the joints of the valve cover, cylinder head and camshaft bracket (No. 1) as shown in the illustration.

    Click image to see an enlarged view

    Fig. Valve cover sealant application-2.5L engine

  4.  
  5. Refer to figure -A- in the illustration to apply liquid gasket to the joint part of the camshaft (No. 1) and cylinder head.
  6.  
  7. Refer to figure -B- in the illustration to apply liquid gasket at 90 degrees to figure -A-.
  8.  
  9. Install a new valve cover gasket to the valve cover.
  10.  
  11. Install the valve cover. Torque the retaining bolts to 18 inch lbs. and then to 73 inch lbs., in the proper sequence as shown in the illustration.
    NOTE
    Be sure that the gasket has not dropped from the grove prior to installation.



    Click image to see an enlarged view

    Fig. Valve cover bolt tightening sequence-2.5L engine

  12.  
  13. Continue the installation in the reverse order of the removal procedure.
  14.  

3.3L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the necessary components in order to gain access to the valve cover retaining bolts.
  6.  
  7. Remove the rocker cover retaining bolts, in the proper sequence.

    Click image to see an enlarged view

    Fig. Valve cover bolt loosening sequence-3.3L engine

  8.  
  9. Remove the rocker cover from the engine.
  10.  

To install:

  1. Be sure to clean the gasket surfaces of the engine and the valve cover.
  2.  
  3. Apply a continuous bead of sealant to the mating surface. Be sure to use the proper grade and type RTV sealant.
  4.  
  5. Torque the retaining bolts to 9-26 inch lbs (1-3 Nm.) and in the proper sequence.

    Click image to see an enlarged view

    Fig. Valve cover bolt tightening sequence-3.3L engine

  6.  

4.0L Engines


Click image to see an enlarged view

Fig. Valve cover and related components-4.0L engine

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the engine cover.
  6.  
  7. Separate the engine harness, by removing the brackets from the rocker covers.
  8.  
  9. Remove the harness bracket from the cylinder head, as required.
  10.  
  11. Remove the ignition coil.
  12.  
  13. Remove the PCV valve hoses from the rocker cover.
  14.  
  15. Remove the oil filler cap from the rocker cover, as required.
  16.  
  17. Loosen the valve cover retaining bolts in the reverse order shown in the illustration.

    Click image to see an enlarged view

    Fig. Valve cover bolt loosening-4.0L engine

  18.  
  19. Remove the valve cover from the engine.
  20.  

To install:

  1. Use a scraper and remove all old gasket material from the cylinder head and camshaft bracket (No. 1).
    NOTE
    Be sure not to scratch the mating surfaces with the scraper when removing the gasket material.

  2.  
  3. Apply genuine RTV silicone sealant or equivalent to the joints of the valve cover, cylinder head and camshaft bracket (No. 1) as shown in the illustration.

    Click image to see an enlarged view

    Fig. Valve cover sealant application (left bank shown)-4.0L engine

  4.  
  5. Refer to figure -A- in the illustration to apply liquid gasket to the joint part of the camshaft (No. 1) and cylinder head.
  6.  
  7. Refer to figure -B- in the illustration to apply liquid gasket to the figure -A- squarely.
  8.  
  9. Install a new valve cover gasket to the valve cover.
  10.  
  11. Install the valve cover. Torque the retaining bolts to 17 inch lbs. and then to 74 inch lbs., in the proper sequence as shown in the illustration.
    NOTE
    Be sure that the gasket has not dropped from the grove prior to installation.



    Click image to see an enlarged view

    Fig. Valve cover bolt tightening sequence-4.0L engine

  12.  
  13. Continue the installation in the reverse order of the removal procedure.
  14.  
  15. When installing the PCV hose, insert it 0.98-1.18 inch from the connector end.
  16.  
  17. When installing the PCV hose between the right and left valve covers be sure the identification paint mark is facing upward (right cover side).
  18.  

 
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