S10 Pickup, Sonoma 2000-2004

Cylinder Head

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Removal & Installation



4.3L Engine
  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Drain the engine cooling system.
  4.  
  5. Remove or disconnect the following:

    Intake manifold
     
    Exhaust manifold
     
    Alternator and bracket, if removing the right cylinder head
     
    Cooling fan assembly
     
    Air conditioning compressor (position it aside with the refrigerant lines attached)
     
    Air pipe bracket and nut from the rear of the power steering pump if removing the left cylinder head
     
    Engine accessory bracket with power steering pump (position the pump aside with the lines attached) and brackets, if removing the left cylinder head
     
    Wiring harness and clip from the rear of the cylinder head
     
    Coolant sensor wire
     
    Wiring from the spark plugs
     
    Spark plugs, if necessary
     
    Ground wires and if necessary, the fuel line bracket from the rear of the cylinder head
     
    Rocker arm cover
     

  6.  
  7. Loosen the rocker arms and remove the pushrods.
    NOTE
    If valve train components, such as the rocker arms or pushrods, are to be reused, they must be tagged or arranged to insure installation in their original locations.

  8.  
  9. Unfasten the cylinder head bolts by loosening them in the reverse of the torque sequence, then carefully remove the cylinder head.

    Click image to see an enlarged view

    Fig. Cylinder head and related components-4.3L engine

  10.  

To install:

  1. Carefully clean and inspect the cylinder head and the gasket mounting surfaces.
    NOTE
    The gasket surfaces on both the head and block must be clean of any foreign matter and free of nicks or heavy scratches. The cylinder bolt threads in the block and thread on the bolts must be cleaned (dirt will affect the bolt torque).


    NOTE
    DO NOT apply sealer to composition steel-asbestos gaskets.

  2.  
  3. If using a steel only gasket, apply a thin and even coat of sealer to both sides of the gaskets.
  4.  
  5. Place a new gasket over the dowel pins with the bead or the words -This Side Up'' facing upward (as applicable), then carefully lower the cylinder head into position over the gasket and dowels.
  6.  
  7. Apply a coating of 12346004 or equivalent sealer to the threads of the cylinder head bolts, then thread the bolts into position until finger-tight.

    Click image to see an enlarged view

    Fig. Cylinder head bolt torque sequence-4.3L engine

  8.  
  9. Install the bolts in sequence to 22 ft. lbs. (30 Nm). The bolts must then be tightened again in sequence in the following order:
    1. Short length bolts: (11, 7, 3, 2, 6, 10) 55 degrees.
    2.  
    3. Medium length bolts: (12, 13) 65 degrees.
    4.  
    5. Long length bolts: (1, 4, 8, 5, 9) 75 degrees.
    6.  

  10.  
  11. Install or connect the following:

    Pushrods, secure the rocker arms and adjust the valves
     
    Rocker arm cover
     
    Spark plugs, if removed
     
    Spark plug wires
     
    Attach the fuel line bracket (if removed) and ground wires to the rear of the head and tighten the bolts to 22 ft. lbs. (30 Nm)
     
    Air conditioning compressor and bracket, if the left cylinder head was removed
     
    Alternator and bracket, if the right cylinder head was removed
     
    Engine accessory bracket with power steering pump if the left cylinder head was removed
     
    Air pipe bracket and nut to the rear of the power steering pump (if equipped), if the left cylinder head was removed. Tighten the nut to 30 ft. lbs. (41 Nm).
     
    A/C compressor, if the left cylinder head was removed
     
    Cooling fan assembly, if the left cylinder head was removed
     
    Wiring harness and clip to the rear of the cylinder head
     
    Coolant sensor wire
     
    Exhaust manifold
     
    Intake manifold
     
    Negative battery cable
     

  12.  
  13. Properly refill the engine cooling system.
  14.  
  15. Run the engine to check for leaks.
  16.  

 
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