GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Cylinder Head

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REMOVAL & INSTALLATION



2.2L Engine

See Figures 1 through 11


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Drain the engine cooling system, then disconnect the air duct from the air inlet.
  4.  
  5. Disconnect the upper radiator hose, then remove the upper fan shroud.
  6.  
  7. Remove the radiator assembly, then remove the lower fan shroud.
  8.  
  9. Remove the fan assembly, then remove the serpentine drive belt.
  10.  
  11. Remove the water pump.
  12.  
  13. Disconnect the heater hose from the intake manifold and the thermostat housing, then remove the thermostat housing.
  14.  
  15. Remove the alternator support brace and disengage the alternator wiring.
  16.  
  17. If equipped, remove the A/C compressor with brackets, then position them aside. DO NOT disconnect the refrigerant lines, but be careful not to kink and damage them. In some cases the A/C compressor can remain attached to the accessory bracket as long as the rear pencil brace is removed. This will enable the compressor to be sat aside when sitting the accessory bracket aside.
  18.  



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Fig. Fig. 1: Location of the accessory bracket bolts (1) and the water outlet assembly bolts (2)



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Fig. Fig. 2: Remove the water outlet assembly from the engine



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Fig. Fig. 3: Move the accessory bracket to one side with the A/C compressor and power steering pump still attached. Do not disconnect either of the components lines



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Fig. Fig. 4: Location of the cylinder head retaining bolt holes



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Fig. Fig. 5: After unfasten the cylinder head bolts, remove it from the engine block



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Fig. Fig. 6: Remove and discard the old cylinder head gasket



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Fig. Fig. 7: Use a scraper to remove the old gasket material from the block and the cylinder head



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Fig. Fig. 8: A new gasket will marked on one side to tell you which side should be facing up



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Fig. Fig. 9: You must use a torque wrench ...



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Fig. Fig. 10: ... and a torque angle meter to properly tighten the head bolts to specification

  1. Disconnect and reposition the accessory bracket along with the alternator and P/S pump and if possible, the A/C compressor still attached. Be careful not to damage the steering pump or A/C lines.
  2.  
  3. Disconnect the throttle cable and cable support linkage, then disconnect the heater hose from the water pump.
  4.  
  5. If necessary, remove the oil fill tube.
  6.  
  7. Disconnect the exhaust pipe and unplug the oxygen sensor electrical connection.
  8.  
  9. Unfasten the exhaust manifold bolts, then remove the manifold.
  10.  
  11. Tag and disconnect both the electrical wiring and the vacuum hoses from the upper intake manifold.
  12.  
  13. Remove the upper intake manifold, then tag and disconnect the wiring from the lower intake manifold.
  14.  
  15. Disconnect the fuel lines, then tag and disengage the spark plug wires.
  16.  
  17. Remove the lower intake manifold from the engine.
  18.  
  19. If equipped, remove the EGR adapter.
  20.  
  21. Remove the rocker arm cover from the cylinder head.
  22.  
  23. Remove the rocker arms and pushrods.
  24.  
  25. Disconnect the engine lift bracket from the rear of the engine.
  26.  
  27. Remove the cylinder head bolts and studs, then carefully lift the cylinder head from the engine.
  28.  

To install:
  1. Carefully clean and inspect cylinder head and the gasket mounting surfaces. Refer to the ENGINE RECONDITIONING procedures at the end of this section.
  2.  

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).

  1. Place a new gasket over the dowel pins (DO NOT use any sealer on the gasket), then position the cylinder head over the gasket and dowels.
  2.  
  3. Apply a coating of 1052080 or equivalent sealer to the cylinder head bolt threads. Install the cylinder head bolts (within 15 minutes of sealer application), then tighten them in the proper sequence first to a torque of 46 ft. lbs. (63 Nm) for long bolts or to 43 ft. lbs. (58 Nm) for short bolts and then tighten all bolts an additional 90 degree turn using a torque angle meter.
  4.  



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Fig. Fig. 11: Cylinder head bolt torque sequence-2.2L engine

  1. Install the engine lift bracket.
  2.  
  3. Install the rocker arms and pushrods.
  4.  
  5. Install the rocker arm cover.
  6.  
  7. Install the lower intake manifold. Refer to the procedure earlier in this section for specifications.
  8.  
  9. If equipped, install the EGR adapter.
  10.  
  11. Connect the spark plug wires and the fuel lines.
  12.  
  13. Attach the wiring to the lower intake manifold.
  14.  
  15. Install the upper intake manifold. Refer to the procedure earlier in this section for specifications.
  16.  
  17. Connect the vacuum hoses and electrical wiring to the upper intake, as tagged during removal.
  18.  
  19. Install the oil fill tube assembly.
  20.  
  21. Install the exhaust manifold, then connect the exhaust pipe and oxygen sensor.
  22.  
  23. Connect the heater hose to the water pump, then connect the throttle cable support and throttle cable.
  24.  
  25. Install the accessory support bracket and components.
  26.  
  27. If not already done, reposition and secure the A/C compressor.
  28.  
  29. Install the power steering support brace and the alternator support brace. Engage the alternator wiring.
  30.  
  31. Install the thermostat housing, then connect the heater hose to the housing.
  32.  
  33. Install the water pump pulley and the serpentine drive belt.
  34.  
  35. Install the fan assembly, then engage the radiator and the lower fan shroud.
  36.  
  37. Install the upper fan shroud, then connect the upper radiator hose.
  38.  
  39. Engage the air inlet duct work, then connect the negative battery cable.
  40.  
  41. Properly refill the engine cooling system and check for leaks.
  42.  

4.3L Engine
1994-95 MODELS

See Figures 12 through 17



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Fig. Fig. 12: Loosen the cylinder head bolts in the reverse order of the torque sequence



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Fig. Fig. 13: Remove the cylinder head from the engine



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Fig. Fig. 14: Remove and discard the old cylinder head gasket



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Fig. Fig. 15: Place rags or shop towels in the combustion chambers before cleaning the old gasket from the block



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Fig. Fig. 16: Tighten the cylinder head bolts in sequence using a torque wrench


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Drain the engine cooling system.
  4.  
  5. Remove the rocker arm cover.
  6.  
  7. Remove the intake manifold.
  8.  
  9. Remove the exhaust manifold.
  10.  
  11. If removing the right cylinder head, remove or disconnect:

    Electrical connector at the sensor.
     
    Dipstick tube at the cylinder head bracket.
     
    Air conditioning compressor (position it aside with the refrigerant lines attached), if equipped.
     
    A/C compressor (if equipped)/belt tensioner bracket.
     

  12.  
  13. If removing the left cylinder head, remove or disconnect:

    Alternator (position it aside).
     
    Left side engine accessory bracket with power steering pump (position the pump aside with the lines attached) and brackets, if equipped.
     

  14.  
  15. Tag and disconnect the wiring from the spark plugs. If necessary, remove the spark plugs from the cylinder head.
  16.  
  17. Loosen the rocker arms and remove the pushrods.
  18.  

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.

  1. Unfasten the cylinder head bolts by loosening them in the reverse of the torque sequence, then carefully remove the cylinder head.
  2.  

To install:
  1. Carefully clean and inspect the cylinder head and the gasket mounting surfaces. Refer to the ENGINE RECONDITIONING procedures at the end of this section.
  2.  

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).



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Fig. Fig. 17: Cylinder head bolt torque sequence-4.3L engine

DO NOT apply sealer to composition steel-asbestos gaskets.

  1. If using a steel only gasket, apply a thin and even coat of sealer to both sides of the gaskets.
  2.  
  3. Place a new gasket over the dowel pins with the bead or the words "This Side Up'' facing upwards (as applicable), then carefully lower the cylinder head into position over the gasket and dowels.
  4.  
  5. Apply a coating of 1052080 or equivalent sealer to the threads of the cylinder head bolts, then thread the bolts into position until finger-tight. Using the proper torque sequence, tighten the bolts in 3 steps:

    First, tighten the bolts to 25 ft. lbs. (34 Nm).
     
    Next, tighten the bolts to 45 ft. lbs. (61 Nm).
     
    Finally, tighten the bolts to 65 ft. lbs. (90 Nm).
     

  6.  
  7. Install the pushrods, secure the rocker arms and adjust the valves.
  8.  
  9. If removed, install the spark plugs. Engage the spark plug wires.
  10.  
  11. If the left cylinder head was removed, reposition and secure the engine accessory bracket with the power steering pump and brackets, as equipped. Install the alternator.
  12.  
  13. If the right cylinder head was removed, install the A/C compressor (if equipped) and A/C compressor/belt tensioner bracket, then install the dipstick tube bracket and engage the sensor electrical connector.
  14.  
  15. Install the exhaust manifold.
  16.  
  17. Install the intake manifold.
  18.  
  19. Install the rocker arm cover.
  20.  
  21. Connect the negative battery cable, then properly refill the engine cooling system.
  22.  
  23. Run the engine to check for leaks, then check and/or adjust the ignition timing.
  24.  

1996-99 MODELS

See Figure 17


CAUTION
Relieve the pressure on the fuel system before disconnecting any fuel line connection. Please refer to Routine Maintenance of this guide for the proper procedures.

  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Drain the engine cooling system.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the exhaust manifold.
  8.  
  9. If removing the right cylinder head, remove the alternator and bracket.
  10.  
  11. On 1999 and later models, remove the cooling fan assembly.
  12.  
  13. If removing the left cylinder head, remove the air conditioning compressor (position it aside with the refrigerant lines attached), if equipped.
  14.  
  15. If removing the left cylinder head, on 1999 and later models, if equipped remove the air pipe bracket and nut from the rear of the power steering pump.
  16.  
  17. If removing the left cylinder head, remove the engine accessory bracket with power steering pump (position the pump aside with the lines attached) and brackets, if equipped.
  18.  
  19. Tag and disengage the wiring harness and clip from the rear of the cylinder head.
  20.  
  21. Disconnect the coolant sensor wire.
  22.  
  23. Tag and disconnect the wiring from the spark plugs. If necessary, remove the spark plugs from the cylinder head.
  24.  
  25. On 1999 and later models, remove the ground wires and if necessary, the fuel line bracket from the rear of the cylinder head
  26.  
  27. Remove the rocker arm cover.
  28.  
  29. Loosen the rocker arms and remove the pushrods.
  30.  

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.

  1. Unfasten the cylinder head bolts by loosening them in the reverse of the torque sequence, then carefully remove the cylinder head.
  2.  

To install:
  1. Carefully clean and inspect the cylinder head and the gasket mounting surfaces. Refer to the ENGINE RECONDITIONING procedures at the end of this section.
  2.  

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).

DO NOT apply sealer to composition steel-asbestos gaskets.

  1. If using a steel only gasket, apply a thin and even coat of sealer to both sides of the gaskets.
  2.  
  3. Place a new gasket over the dowel pins with the bead or the words "This Side Up'' facing upwards (as applicable), then carefully lower the cylinder head into position over the gasket and dowels.
  4.  
  5. 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.
  6.  
  7. 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.  

  8.  
  9. Install the pushrods, secure the rocker arms and adjust the valves.
  10.  
  11. Install the rocker arm cover.
  12.  
  13. If removed, install the spark plugs. Engage the spark plug wires.
  14.  
  15. On 1999-99 models, 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).
  16.  
  17. If the left cylinder head was removed, reposition and secure the air conditioning compressor and bracket.
  18.  
  19. If the right cylinder head was removed, install the alternator and bracket.
  20.  
  21. If the left cylinder head was removed, install the engine accessory bracket with power steering pump.
  22.  
  23. If the left side cylinder head was removed on 1999 models, attach the air pipe bracket and nut to the rear of the power steering pump (if equipped). Tighten the nut to 30 ft. lbs. (41 Nm).
  24.  
  25. If the left cylinder head was removed, install the A/C compressor.
  26.  
  27. If the left side cylinder head was removed on 1999 models, install the cooling fan assembly.
  28.  
  29. Engage the wiring harness and clip from the rear of the cylinder head.
  30.  
  31. Connect the coolant sensor wire.
  32.  
  33. Install the exhaust manifold.
  34.  
  35. Install the intake manifold.
  36.  
  37. Connect the negative battery cable, then properly refill the engine cooling system.
  38.  
  39. Run the engine to check for leaks.
  40.  

 
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