GM Full Size Vans 1987-1997 Repair Guide

Cylinder Head

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REMOVAL & INSTALLATION




CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

4.3L Engine

See Figures 1, 2, 3, 4, 5, 6, 7 and 8



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Fig. Fig. 1: Prepare the cylinder head by removing the rocker arm cover, intake manifold and exhaust manifold



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Fig. Fig. 2: Loosen the cylinder head bolts using the reverse order of the tightening sequence



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Fig. Fig. 3: A breaker bar, socket and various length extensions are necessary to remove the bolts

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine cover.
  4.  
  5. Drain the coolant.
  6.  
  7. Remove the intake manifold.
  8.  
  9. Remove the exhaust manifold.
  10.  
  11. If applicable, remove the air pipe at the rear of the right cylinder head.
  12.  
  13. Remove the alternator mounting bolt at the right cylinder head and, if necessary, the alternator.
  14.  
  15. Remove the power steering pump and brackets from the left cylinder head, and lay them aside.
  16.  
  17. Remove the air conditioner compressor, and lay it aside. Remove the spark plug wires at their brackets, the ground strap from the right side and the coolant sensor wire from the left head.
  18.  
  19. Remove the cylinder cover.
  20.  
  21. Remove the spark plugs.
  22.  
  23. Remove the pushrods.
  24.  
  25. Remove the cylinder head bolts in the reverse order of the tightening sequence.
  26.  
  27. Remove the cylinder head and gasket.
  28.  



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Fig. Fig. 4: Once all the bolts are removed, break the gasket seal and lift the cylinder head from the block



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Fig. Fig. 5: Protect the lifter valley and piston bores using rags or a plastic cover ...



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Fig. Fig. 6: ... then carefully clean all the old gasket and debris from the gasket mating surfaces

To install:
  1. Clean all gasket mating surfaces, install a new gasket and reinstall the cylinder head. Install the cylinder heads using new gaskets. Make sure the gasket has the word HEAD up.
  2.  

Coat a steel gasket on both sides with sealer. If a composition gasket is used, do not use sealer.

  1. Clean the cylinder head bolts, apply sealer to the threads, and install them hand-tight.
  2.  



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Fig. Fig. 7: Upon installation, tighten the cylinder head bolts in the proper sequence

  1. Tighten the head bolts a little at a time in the sequence shown. Tighten the bolts in three stages:1987-95 models:

    First pass: 25 ft. lbs. (34 Nm)
     
    Second pass: 45 ft. lbs. (61 Nm)
     
    Final pass: 65 ft. lbs. (90 Nm)On 1996-97 models install the bolts in sequence to 22 ft. lbs. (30 Nm). The bolts must then be tightened again in sequence in the following order:
     
    Short length bolt: (11, 7, 3, 2, 6, 10) 55 degrees
     
    Medium length bolt: (12, 13) 65 degrees
     
    Long length bolts: (1, 4, 8, 5, 9) 75 degrees
     

  2.  



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Fig. Fig. 8: Cylinder head bolt tightening sequence - 1987-97 4.3L engines

  1. Install the pushrods.
  2.  
  3. If necessary, adjust the rocker arms.
  4.  
  5. Install the spark plugs.
  6.  
  7. Install the rocker arm cover.
  8.  
  9. Install the air conditioner compressor.
  10.  
  11. Install the power steering pump and brackets.
  12.  
  13. Install the alternator or the alternator mounting bolt at the cylinder head.
  14.  
  15. If removed, install the air pipe at the rear of the head.
  16.  
  17. Install the exhaust manifold.
  18.  
  19. Install the intake manifold.
  20.  
  21. Fill the engine with coolant.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Install the engine cover.
  26.  

5.0L and 5.7L Engines

See Figures 9, 10, 11, 12, 13 and 14

  1. Disconnect the negative battery cable and drain the coolant.
  2.  
  3. Remove the engine cover.
  4.  
  5. If applicable, remove the coolant recovery reservoir.
  6.  
  7. Remove the intake manifold.
  8.  
  9. Remove the exhaust manifolds and position them out of the way.
  10.  
  11. Remove the ground strap at the rear of the right AIR pipe, If equipped.
  12.  
  13. If the van is equipped with air conditioning, remove the air conditioning compressor and the forward mounting bracket and lay the compressor aside. Do not disconnect any of the refrigerant lines.
  14.  
  15. Remove the EGR inlet tube.
  16.  
  17. On the right side cylinder head, disconnect the fuel pipe and move it out of the way. Remove the spark plug wires and disconnect the wiring harness bracket.
  18.  
  19. Remove the nut and stud attaching the main accessory bracket to the cylinder head. You may have to loosen the remaining bolts and studs in order to remove the head.
  20.  
  21. Tag and disconnect the coolant sensor wire. Remove the spark plug wire bracket.
  22.  
  23. Remove the cylinder head covers. Remove the spark plugs.
  24.  
  25. Back off the rocker arm nuts and pivot the rocker arms out of the way so that the pushrods can be removed. Identify the pushrods so that they can be installed in their original positions.
  26.  
  27. Remove the cylinder head bolts in the reverse order of the tightening sequence and then remove the heads.
  28.  



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Fig. Fig. 9: Using a breaker bar remove the cylinder head bolts in the reverse order of the tightening sequence



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Fig. Fig. 10: After removing all the cylinder head bolts remove the cylinder head

To install:
  1. Inspect the cylinder head and block mating surfaces. Clean all old gasket material.
  2.  
  3. Install the cylinder heads using new gaskets. Install the gaskets with the word HEAD up.
  4.  

Coat a steel gasket on both sides with sealer. If a composition gasket is used, do not use sealer.

  1. Clean the bolts, apply sealer to the threads, and install them hand-tight.
  2.  
  3. Tighten the cylinder head bolts a little at a time, in the sequence shown. Tighten the bolts in three stages:1987-95 models.

    First pass: 25 ft. lbs. (34 Nm)
     
    Second pass: 45 ft. lbs. (61 Nm)
     
    Final pass: 65 ft. lbs. (90 Nm)On 1996- models install the bolts in sequence to 22 ft. lbs. (30 Nm). The bolts must then be tightened again in sequence in the following order:
     
    Short length bolt: (3, 4, 7, 8, 11, 12, 15, 16) 55 degrees
     
    Medium length bolt: (14, 17) 65 degrees
     
    Long length bolts: (1, 2, 5, 6, 9, 10, 13) 75 degrees
     

  4.  
  5. Install the pushrods so that they are in their original positions. Swing the rocker arms into position and tighten the bolts.
  6.  
  7. Install the cylinder head covers. Install the spark plugs.
  8.  
  9. Connect the coolant sensor wire. Install the spark plug wire bracket.
  10.  
  11. Install main accessory bracket to the cylinder head.
  12.  
  13. Install the EGR vent tube.
  14.  
  15. Connect the fuel pipe. Install the spark plug wires and Connect the wiring harness bracket.
  16.  
  17. Install the air conditioning compressor and the forward mounting bracket.
  18.  
  19. Connect the ground strap to the rear of the right AIR pipe.
  20.  
  21. Install the exhaust manifolds.
  22.  
  23. Install the intake manifold.
  24.  
  25. If removed, install the coolant recovery reservoir.
  26.  
  27. Connect the negative battery cable and fill the engine with coolant.
  28.  
  29. Install the engine cover.
  30.  



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Fig. Fig. 11: Remove and discard the old cylinder head gasket



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Fig. Fig. 12: Using a scraper remove the old gasket residue from both mating surfaces



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Fig. Fig. 13: Cylinder head bolt tightening sequence - 1987-96 5.0L and 5.7L engines



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Fig. Fig. 14: Using a torque wrench, tighten the cylinder head bolts in sequence

6.2L and 6.5L Diesel Engines

See Figure 15

RIGHT SIDE
  1. Disconnect the negative battery cable. Drain the cooling system.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the fuel injection lines. Refer to Fuel System for this procedure.
  8.  
  9. Remove the cruise control transducer (if so equipped).
  10.  
  11. Remove the upper fan shroud.
  12.  
  13. Remove the air conditioning compressor belt.
  14.  
  15. Remove the exhaust manifold.
  16.  
  17. Disconnect and label the glow plug wiring. Use a proper removal tool. DO NOT pull on the harness wire!
  18.  
  19. Remove the oil dipstick tube.
  20.  
  21. Remove the oil fill tube upper bracket.
  22.  
  23. Remove the rocker arm cover(s), after removing any accessory brackets which interfere with cover removal.
  24.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize you exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

  1. Remove the rocker arm assemblies. It is a good practice to number or mark the parts to avoid interchanging them.
  2.  
  3. Remove the pushrods. Keep them in order.
  4.  
  5. Remove the air cleaner resonator and bracket.
  6.  
  7. Remove the automatic transmission dipstick and tube.
  8.  
  9. Drain the cooling system.
  10.  
  11. Disconnect the heater hoses at the head.
  12.  
  13. Disconnect the upper radiator hose.
  14.  
  15. Disconnect the bypass hose.
  16.  
  17. Remove the alternator upper bracket.
  18.  
  19. Remove the coolant crossover pipe and thermostat.
  20.  
  21. Remove the head bolts.
  22.  
  23. Remove the cylinder head.
  24.  

To install:


Click image to see an enlarged view

Fig. Fig. 15: Cylinder head bolt tightening sequence - diesel engines

  1. Clean the mating surfaces of the head and block thoroughly.
  2.  
  3. Install a new head gasket on the engine block. Do NOT coat the gaskets with any sealer on either engine. The gaskets have a special coating that eliminates the need for sealer. The use of sealer will interfere with this coating and cause leaks. Install the cylinder head onto the block.
  4.  
  5. Clean the head bolts thoroughly. The left rear head bolt must be installed into the head prior to head installation. Coat the threads and heads of the head bolts with sealing compound (GM part #1052080 or equivalent) before installation. Tighten the head bolts in three stages: 20 ft. lbs. (25 Nm); 50 ft. lbs. (68 Nm) and finally, 1 / 4 turn more.
  6.  
  7. Install the coolant crossover pipe and thermostat.
  8.  
  9. Install the alternator upper bracket.
  10.  
  11. Connect the bypass hose.
  12.  
  13. Connect the upper radiator hose.
  14.  
  15. Connect the heater hoses at the head.
  16.  
  17. Install the automatic transmission dipstick and tube.
  18.  
  19. Install the air cleaner resonator and bracket.
  20.  
  21. Install the pushrods.
  22.  
  23. Install the rocker arm assemblies.
  24.  
  25. Adjust the valves.
  26.  
  27. Install the rocker arm cover(s).
  28.  
  29. Install the oil fill tube upper bracket.
  30.  
  31. Install the oil dipstick tube.
  32.  
  33. Connect the glow plug wiring.
  34.  
  35. Install the exhaust manifold.
  36.  
  37. Install the air conditioning compressor belt.
  38.  
  39. Install the upper fan shroud.
  40.  
  41. Install the cruise control transducer.
  42.  
  43. Install the fuel injection lines. see Fuel System .
  44.  
  45. Install the intake manifold.
  46.  
  47. Fill the cooling system and connect the battery cable.
  48.  

LEFT SIDE
  1. Disconnect the negative battery cable and drain the cooling system.
  2.  
  3. Remove the engine cover.
  4.  
  5. If necessary, remove the coolant recovery reservoir.
  6.  
  7. Remove the intake manifold.
  8.  
  9. Remove the fuel injection lines. see Fuel System .
  10.  
  11. Remove the cruise control transducer.
  12.  
  13. Remove the upper fan shroud.
  14.  
  15. Remove the air conditioning compressor belt.
  16.  
  17. Remove the exhaust manifold.
  18.  
  19. Remove the power steering pump lower adjusting bolts.
  20.  
  21. Disconnect and label the glow plug wiring.
  22.  
  23. Remove the air conditioning compressor and position it out of the way. DO NOT DISCONNECT ANY REFRIGERANT LINES!
  24.  
  25. Remove the power steering pump and position it out of the way. DO NOT DISCONNECT THE FLUID LINES!
  26.  
  27. Remove the oil dipstick tube.
  28.  
  29. Disconnect the transmission detent cable.
  30.  
  31. Remove the glow plug controller and bracket.
  32.  
  33. Remove the rocker arm cover(s), after removing any accessory brackets which interfere with cover removal.
  34.  
  35. Remove the rocker arm assemblies. It is a good practice to number or mark the parts to avoid interchanging them.
  36.  
  37. Remove the pushrods. Keep them in order.
  38.  
  39. Remove the air cleaner resonator and bracket.
  40.  
  41. Remove the automatic transmission dipstick and tube.
  42.  
  43. Remove the alternator upper bracket.
  44.  
  45. Remove the coolant crossover pipe and thermostat.
  46.  
  47. Remove the head bolts.
  48.  
  49. Remove the cylinder head.
  50.  

To install:
  1. Clean the mating surfaces of the head and block thoroughly.
  2.  
  3. Install a new head gasket on the engine block. Do NOT coat the gaskets with any sealer on either engine. The gaskets have a special coating that eliminates the need for sealer. The use of sealer will interfere with this coating and cause leaks. Install the cylinder head onto the block.
  4.  
  5. Clean the head bolts thoroughly. The left rear head bolt must be installed into the head prior to head installation. Coat the threads and heads of the head bolts with sealing compound (GM part #1052080 or equivalent) before installation. Tighten the head bolts in three stages: 20 ft. lbs. (25 Nm); 50 ft. lbs. (68 Nm) and finally, 1 / 4 turn more.
  6.  
  7. Install the coolant crossover pipe and thermostat.
  8.  
  9. Install the alternator upper bracket.
  10.  
  11. Install the automatic transmission dipstick and tube.
  12.  
  13. Install the air cleaner resonator and bracket.
  14.  
  15. Install the pushrods.
  16.  
  17. Install the rocker arm assemblies.
  18.  
  19. Adjust the valves.
  20.  
  21. Install the rocker arm cover(s).
  22.  
  23. Install the oil fill tube upper bracket.
  24.  
  25. Install the oil dipstick tube.
  26.  
  27. Connect the glow plug wiring.
  28.  
  29. Install the compressor.
  30.  
  31. Install the power steering pump.
  32.  
  33. Install the glow plug controller.
  34.  
  35. Install the exhaust manifold.
  36.  
  37. Connect the detent cable.
  38.  
  39. Install the air conditioning compressor belt.
  40.  
  41. Install the upper fan shroud.
  42.  
  43. Install the cruise control transducer.
  44.  
  45. Install the fuel injection lines. see Fuel System .
  46.  
  47. Install the intake manifold.
  48.  
  49. Install the coolant recovery reservoir, if removed.
  50.  
  51. Connect the battery cable and fill the cooling system.
  52.  
  53. Install the engine cover.
  54.  

7.4L Engines

See Figure 16

  1. Disconnect the negative battery cable and drain the cooling system.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the exhaust manifolds.
  8.  
  9. Remove the alternator and bracket.
  10.  
  11. Remove the AIR pump, if equipped.
  12.  
  13. If the vehicle is equipped with air conditioning, remove the air conditioning compressor and the forward mounting bracket and lay the compressor aside. Do not disconnect any of the refrigerant lines.
  14.  
  15. Remove the rocker arm cover.
  16.  
  17. Remove the spark plugs.
  18.  



Click image to see an enlarged view

Fig. Fig. 16: Cylinder head bolt tightening sequence - 1987-96 7.4L engines

  1. Remove the AIR pipes at the rear of the head, if equipped.
  2.  
  3. Disconnect the ground strap at the rear of the head.
  4.  
  5. Disconnect the temperature sensor wire.
  6.  
  7. Back off the rocker arm nuts and pivot the rocker arms out of the way so that the pushrods can be removed. Identify the pushrods so that they can be installed in their original positions.
  8.  
  9. Remove the cylinder head bolts and remove the heads.
  10.  

To install:

The cylinder head should be cleaned and inspected for warpage or damage before installation. Refer to the cleaning and inspection procedures in the engine reconditioning portion of this section.

  1. Thoroughly clean the mating surfaces of the head and block. Clean the bolt holes thoroughly.
  2.  
  3. Install the cylinder heads using new gaskets. Install the gaskets with the word HEAD up.
  4.  

Coat a steel gasket on both sides with sealer. If a composition gasket is used, do not use sealer.

  1. Clean the bolts, apply sealer to the threads, and install them hand-tight.
  2.  
  3. Tighten the head bolts a little at a time in the sequence shown. On 1987-95 models, tighten the bolts in three stages: 30 ft. lbs. (40 Nm), 60 ft. lbs. (80 Nm) and finally to 81 ft. lbs. (110 Nm). On 1996-97 models tighten the bolts in three stages: 30 ft. lbs. (40 Nm), 60 ft. lbs. (80 Nm) and finally to 85 ft. lbs. (115 Nm).
  4.  
  5. Install the intake and exhaust manifolds.
  6.  
  7. Install the pushrods.
  8.  
  9. Install the rocker arms and adjust them as described in this section.
  10.  
  11. Connect the temperature sensor wire.
  12.  
  13. Connect the ground strap at the rear of the head.
  14.  
  15. Install the AIR pipes at the rear of the head.
  16.  
  17. Install the spark plugs.
  18.  
  19. Install the rocker arm cover.
  20.  
  21. Install the air conditioning compressor and the forward mounting bracket.
  22.  
  23. Install the AIR pump.
  24.  
  25. Install the alternator.
  26.  
  27. Connect the battery cable and refill the cooling system.
  28.  
  29. Install the engine cover.
  30.  

 
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