GM Full-Size Trucks 1988-1998 Repair Information

Engine

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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.

4.8L Engines

See Figures 1, 2 and 3

  1. Matchmark and remove the hood.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the battery.
  6.  
  7. Drain the cooling system.
  8.  
  9. Drain the engine oil.
  10.  
  11. Disconnect the accelerator cable from the carburetor throttle lever.
  12.  
  13. On trucks with automatic transmission, remove the detent cable from the throttle lever.
  14.  
  15. Remove the air cleaner assembly.
  16.  
  17. Mark and disconnect all necessary electrical wiring from the engine.
  18.  
  19. Mark and disconnect all necessary vacuum hoses from the engine.
  20.  
  21. Disconnect the radiator hoses at the radiator.
  22.  
  23. Disconnect the heater hoses at the engine.
  24.  
  25. Remove the radiator.
  26.  


CAUTION
Please refer to Routine Maintenance before discharging the compressor or disconnecting air conditioning lines. Damage to the air conditioning system or personal injury could result. Consult your local laws concerning refrigerant discharge and recycling. In many areas it may be illegal for anyone but a certified technician to service the A/C system. Always use an approved recovery station when discharging the air conditioning.

  1. On trucks with air conditioning, discharge the system using an approved recovery/recycling machine.
  2.  
  3. Remove the air conditioning condenser.
  4.  
  5. Remove the fan assembly and water pump pulley.
  6.  
  7. Disconnect and plug the fuel line at the fuel pump.
  8.  
  9. Raise and support the truck on jackstands.
  10.  
  11. Remove the starter.
  12.  
  13. Remove the flywheel cover.
  14.  
  15. Disconnect the exhaust pipe from the exhaust manifold.
  16.  
  17. Support the weight of the engine with a shop crane and remove the engine mount through-bolts.
  18.  



Click image to see an enlarged view

Fig. Fig. 1: Front engine mounts-4.8L engines, 10/1500 series



Click image to see an enlarged view

Fig. Fig. 2: Front engine mounts-4.8L engines, 20/2500 and 30/3500 series



Click image to see an enlarged view

Fig. Fig. 3: Rear engine mounts-4.8L engines

  1. If equipped with an automatic transmission, remove the torque converter-to-flexplate bolts.
  2.  
  3. If equipped with 4WD, unbolt the strut rods at the engine mounts.
  4.  
  5. Remove the bellhousing-to-engine retaining bolts.
  6.  
  7. Support the transmission with a floor jack.
  8.  
  9. Using the shop crane, carefully remove the engine from the vehicle.
  10.  

To install:
  1. Using the shop crane, carefully lower the engine into the truck.
  2.  
  3. Install the bellhousing-to-engine retaining bolts. Tighten the bolts to 30 ft. lbs. (40 Nm).
  4.  
  5. Remove the floor jack.
  6.  
  7. If equipped with 4WD, bolt the strut rods to the engine mounts. Tighten the bolts to 45 ft. lbs. (61 Nm).
  8.  
  9. If equipped with an automatic transmission, install the torque converter-to-flexplate bolts. Tighten the bolts to 40 ft. lbs. (54 Nm).
  10.  
  11. Install the engine mount through-bolts. Tighten them to 60 ft. lbs. (81 Nm). Remove the shop crane.
  12.  
  13. Connect the exhaust pipe at the exhaust manifold. Tighten the nuts to 20 ft. lbs. (27 Nm).
  14.  
  15. Install the flywheel cover.
  16.  
  17. Install the starter.
  18.  
  19. Lower the truck.
  20.  
  21. Connect the fuel line at the fuel pump.
  22.  
  23. Install the fan assembly and water pump pulley.
  24.  
  25. Install the air conditioning condenser.
  26.  
  27. Install the radiator.
  28.  
  29. Connect the heater hoses at the engine.
  30.  
  31. Connect the radiator hoses at the radiator.
  32.  
  33. Connect all vacuum hoses.
  34.  
  35. Connect all electrical wiring.
  36.  
  37. On trucks with automatic transmission, connect the detent cable at the throttle lever.
  38.  
  39. Connect the accelerator cable at the carburetor throttle lever.
  40.  
  41. Fill the cooling system.
  42.  
  43. Fill the engine crankcase with oil.
  44.  


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. Install the battery.
  2.  
  3. Connect the negative battery cable.
  4.  
  5. Evacuate and charge the air conditioning system.
  6.  
  7. Install air cleaner assembly.
  8.  
  9. Install the hood.
  10.  

4.3L, 5.0L and 5.7L Engines

See Figures 4 and 5

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the hood.
  4.  
  5. Drain the cooling system.
  6.  
  7. Remove the air cleaner assembly.
  8.  
  9. Remove the accessory drive belt, fan and water pump pulley.
  10.  
  11. Remove the radiator and shroud.
  12.  


CAUTION
Please refer to Routine Maintenance before discharging the compressor or disconnecting air conditioning lines. Damage to the air conditioning system or personal injury could result. Consult your local laws concerning refrigerant discharge and recycling. In many areas it may be illegal for anyone but a certified technician to service the A/C system. Always use an approved recovery station when discharging the air conditioning.

  1. On vehicles with air conditioning, discharge the system using an approved recovery/recycling machine.
  2.  
  3. Remove the air conditioning condenser.
  4.  
  5. Disconnect the heater hoses at the engine.
  6.  
  7. Disconnect the accelerator, cruise control and detent linkage (if equipped).
  8.  
  9. Disconnect the air conditioning compressor, (if equipped), and lay aside.
  10.  
  11. Remove the power steering pump and lay aside.
  12.  



Click image to see an enlarged view

Fig. Fig. 4: Front engine mounts-5.0 and 5.7L shown, others similar



Click image to see an enlarged view

Fig. Fig. 5: Rear engine mounts-5.0 and 5.7L shown, others similar

  1. Disconnect the engine wiring harness from the engine.
  2.  
  3. Disconnect and tag the fuel line(s) from the intake manifold to the rear of the block.
  4.  
  5. Disconnect and tag the vacuum lines from the intake manifold.
  6.  
  7. Remove the distributor.
  8.  
  9. Raise the vehicle and support it safely.
  10.  
  11. Drain the engine oil.
  12.  
  13. Disconnect the exhaust pipes from the manifold.
  14.  
  15. Disconnect the strut rods at the engine mountings, (if equipped).
  16.  
  17. Remove the flywheel or torque converter cover.
  18.  
  19. Disconnect the wiring along the oil pan rail.
  20.  
  21. Remove the starter.
  22.  
  23. Disconnect the wire for the fuel gauge.
  24.  
  25. On vehicles equipped with automatic transmission, remove the converter-to-flexplate bolts.
  26.  
  27. Lower the vehicle and suitably support the transmission. Attach a suitable lifting fixture to the engine.
  28.  
  29. Remove the bell housing-to-engine bolts.
  30.  
  31. Remove the rear engine mounting-to-frame bolts and the front through-bolts and remove the engine.
  32.  


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.

To install:
  1. Raise the vehicle and support it safely.
  2.  
  3. Lower the engine and install the engine mounting bolts. Tighten the mounting bolts as follows:
  4.  

1988-96 4.3L C/K Series



Front mount bolts: 44 ft. lbs. (59 Nm)
 
Front through-bolt: 70 ft. lbs. (95 Nm)
 
Front mount nut: 50 ft. lbs. (68 Nm)
 
Rear mount bolts: 35 ft. lbs. (47 Nm)
 

The 1997-98 4.3L C/K models use hollow, Loctite ® coated engine bolts in order to attach the engine mount bracket to the frame. If you remove these bolts they must be replaced with the factory specified bolt.

1997-98 4.3L C/K Series



Mount-to-frame hollow bolts: step 1. in a clockwise sequence to 7 ft. lbs. (10 Nm), step 2. in a clockwise sequence in increments of 5 ft. lbs. (7 Nm) until a final torque of 28 ft. lbs. (38 Nm).
 
Through-bolt : 74 ft. lbs. (100 Nm).
 
Nut: 50 ft. lbs. (68 Nm).
 

1988-91 4.3L R/V Series



Front mount bolts: 36 ft. lbs. (48 Nm)
 
Front mount nut: 33 ft. lbs. (45 Nm)
 
Front through-bolt: 70 ft. lbs. (95 Nm)
 
Front through-bolt nut: 50 ft. lbs. (68 Nm)
 
Rear mount bolts: 35 ft. lbs. (47 Nm)
 

1988-91 5.0L and 5.7L engines



Front mount bolts: 36 ft. lbs. (48 Nm)
 
Front mount nut: 30 ft. lbs. (40 Nm)
 
Front through-bolt: 85 ft. lbs. (115 Nm)
 
Front through-bolt nut: 55 ft. lbs. (75 Nm)
 
Rear mount bolt/nut (R Series): 35 ft. lbs. (47 Nm)
 
Rear mount bolt (V Series): 40 ft. lbs. (54 Nm)
 
Rear mount nut (V Series): 36 ft. lbs. (48 Nm)
 

1992-98 5.0L and 5.7L C/K Series



Front mount frame bolt: 44 ft. lbs. (59 Nm)
 
Front mount frame nut: 33 ft. lbs. (45 Nm)
 
Front through-bolt: 70 ft. lbs. (95 Nm)
 
Front through-bolt nut: 50 ft. lbs. (68 Nm)
 
Front mount engine bolt: 38 ft. lbs. (51 Nm)
 
Rear mount bolts: 35 ft. lbs. (47 Nm)
 

  1. Install the bell housing-to-engine bolts and tighten to 35 ft. lbs. (47 Nm).
  2.  
  3. Remove the transmission support.
  4.  
  5. Install the converter-to-flex bolts and torque to 46 ft. lbs. (63 Nm).
  6.  
  7. Install the fuel gauge wiring and starter.
  8.  
  9. Install the flywheel or torque converter cover.
  10.  
  11. Connect the strut rods at the engine mountings, (if equipped).
  12.  
  13. Install the exhaust pipes at the manifold.
  14.  
  15. Lower the vehicle.
  16.  
  17. Install the distributor.
  18.  
  19. Connect the vacuum lines to the intake manifold.
  20.  
  21. Install the fuel line.
  22.  
  23. Connect the engine wiring harness.
  24.  
  25. Install the power steering pump.
  26.  
  27. Connect the air conditioning compressor.
  28.  
  29. Connect the accelerator, cruise control and detent linkage.
  30.  
  31. Connect the heater hoses.
  32.  
  33. Install the radiator and shroud.
  34.  
  35. Install the accessory drive belts.
  36.  
  37. Install the hood.
  38.  
  39. Install the proper quantity and grade of coolant and engine oil.
  40.  
  41. Connect the negative battery cable.
  42.  

7.4L Engines

See Figures 6 and 7

  1. Remove the hood.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Drain the cooling system.
  6.  
  7. Remove the air cleaner assembly.
  8.  



Click image to see an enlarged view

Fig. Fig. 6: Front engine mounts-7.4L engines



Click image to see an enlarged view

Fig. Fig. 7: Rear engine mount-7.4L engines

  1. Remove the radiator and fan shroud.
  2.  
  3. Disconnect and tag all necessary engine wiring.
  4.  
  5. Disconnect the accelerator, cruise control and TVS linkage.
  6.  
  7. Disconnect the fuel supply lines.
  8.  
  9. Disconnect all necessary vacuum wires.
  10.  
  11. Disconnect the air conditioning compressor and lay aside. Do not disconnect the lines.
  12.  
  13. Dismount the power steering pump and position it out of the way. It's not necessary to disconnect the fluid lines.
  14.  
  15. Raise the vehicle and support it on jackstands.
  16.  
  17. Disconnect the exhaust pipes from the manifold.
  18.  
  19. Remove the starter.
  20.  
  21. Remove the torque converter cover.
  22.  
  23. Remove the converter-to-flexplate bolts.
  24.  
  25. Lower the vehicle and suitably support the transmission. Attach a suitable lifting fixture to the engine.
  26.  
  27. Remove the bellhousing-to-engine bolts.
  28.  
  29. Remove the rear engine mounting-to-frame bolts and the front through-bolts and remove the engine.
  30.  

To install:
  1. Lower the engine and install the engine mounting bolts. Tighten the mounting bolts as follows:
  2.  

1988-91 C/K Series



Front mount frame bolt: 36 ft. lbs. (48 Nm)
 
Front mount engine bolt: 45 ft. lbs. (60 Nm)
 
Front through-bolt: 70 ft. lbs. (95 Nm)
 
Front through-bolt nut: 50 ft. lbs. (68 Nm)
 
Rear mount bolts: 36 ft. lbs. (48 Nm)
 

1988-91 R/V Series



Front mount bolts: 36 ft. lbs. (48 Nm)
 
Front mount nut: 30 ft. lbs. (40 Nm)
 
Front through-bolt: 85 ft. lbs. (115 Nm)
 
Front through-bolt nut: 55 ft. lbs. (75 Nm)
 
Rear mount bolt/nut (R Series): 35 ft. lbs. (47 Nm)
 
Rear mount bolt (V Series): 40 ft. lbs. (54 Nm)
 
Rear mount nut (V Series): 36 ft. lbs. (48 Nm)
 

1992-98 C/K Series



Front mount frame bolt: 44 ft. lbs. (59 Nm)
 
Front mount frame nut: 33 ft. lbs. (45 Nm)
 
Front through-bolt: 70 ft. lbs. (95 Nm)
 
Front through-bolt nut: 50 ft. lbs. (68 Nm)
 
Front mount engine bolt: 38 ft. lbs. (51 Nm)
 
Rear mount bolts: 35 ft. lbs. (47 Nm)
 

  1. Install the bellhousing-to-engine bolts and tighten to 35 ft. lbs. (47 Nm).
  2.  
  3. Remove the engine lifting fixture and transmission jack.
  4.  
  5. Raise the vehicle and support it on jackstands.
  6.  
  7. Install the converter-to-flexplate bolts and tighten them to 46 ft. lbs. (63 Nm).
  8.  
  9. Install the fuel gauge wiring and starter.
  10.  
  11. Install the torque converter cover.
  12.  
  13. Install the starter.
  14.  


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. Install the exhaust pipes at the manifold.
  2.  
  3. Lower the vehicle.
  4.  
  5. Install the power steering pump.
  6.  
  7. Install the air conditioning compressor.
  8.  
  9. Install all vacuum hoses.
  10.  
  11. Install the fuel supply line.
  12.  
  13. Connect the accelerator, cruise control and TVS linkage.
  14.  
  15. Connect the engine wiring.
  16.  
  17. Install the radiator and fan shroud.
  18.  
  19. Install the air cleaner.
  20.  
  21. Install the hood.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Install the proper quantity and grade of coolant.
  26.  

6.2L and 6.5L Diesel Engines

See Figures 8 and 9


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.

  1. Disconnect the negative battery cable.
  2.  
  3. Raise the vehicle and support it safely.
  4.  
  5. Remove the flywheel or torque converter cover.
  6.  
  7. On vehicles equipped with automatic transmission, remove the converter-to-flexplate bolts.
  8.  



Click image to see an enlarged view

Fig. Fig. 8: Front engine mounts-6.2L/6.5L engines



Click image to see an enlarged view

Fig. Fig. 9: Rear engine mounts-6.2L/6.5L engines

  1. Disconnect the exhaust pipes from the manifold.
  2.  
  3. Remove the starter.
  4.  
  5. Remove the bellhousing bolts.
  6.  
  7. Remove the engine mounting through-bolts.
  8.  
  9. Disconnect the block heater wiring.
  10.  
  11. Disconnect the wiring harness, transmission cooler lines, and a battery cable clamp at the oil pan.
  12.  
  13. Disconnect the fuel return lines at the engine.
  14.  
  15. Disconnect the oil cooler lines at the engine.
  16.  
  17. Lower the vehicle.
  18.  
  19. Remove the hood.
  20.  
  21. Drain the cooling system.
  22.  
  23. Remove the air cleaner and cover the mouth of the intake manifold.
  24.  
  25. Remove the alternator wires and clips.
  26.  
  27. Disconnect the wiring at the injector pump.
  28.  
  29. Disconnect the wiring from the rocker cover including the glow plug wires.
  30.  
  31. Disconnect the EGR/EPR solenoids, glow plug controller and temperature solenoid and move the harness aside.
  32.  
  33. Disconnect the left or right ground strap.
  34.  
  35. Remove the upper fan shroud and fan.
  36.  
  37. Disconnect the power steering pump and reservoir and lay to one side.
  38.  
  39. Disconnect the accelerator, cruise control and detent cables at the injection pump.
  40.  
  41. Disconnect the heater hose at the engine.
  42.  
  43. Remove the radiator.
  44.  
  45. Support the transmission with a suitable jack.
  46.  
  47. Remove the engine.
  48.  

To install:
  1. Lower the engine and install the engine mounting bolts.
  2.  

Tighten as follows:


Front mount bolt: 44 ft. lbs. (59 Nm)
 
Front mount nut: 33 ft. lbs. (45 Nm)
 
Bracket-to-block bolt: 38 ft. lbs. (51 Nm)
 
Through-bolt: 70 ft. lbs. (95 Nm)
 
Through-bolt nut: 50 ft. lbs. (68 Nm)
 

  1. Install the bellhousing-to-engine bolts and tighten to 30 ft. lbs. (40 Nm).
  2.  
  3. Remove the engine lifting fixture and transmission jack.
  4.  
  5. Raise the vehicle and support it on jackstands.
  6.  
  7. Install the converter-to-flexplate bolts and tighten to 46 ft. lbs. (63 Nm).
  8.  
  9. Install the fuel gauge wiring and starter.
  10.  
  11. Install the flywheel or torque converter cover.
  12.  
  13. Install the starter.
  14.  
  15. Install the exhaust pipes at the manifold.
  16.  
  17. Connect the wiring harness, transmission cooler lines, and a battery cable clamp at the oil pan.
  18.  
  19. Connect the fuel return lines at the engine.
  20.  
  21. Connect the oil cooler lines at the engine.
  22.  
  23. Lower the vehicle.
  24.  
  25. Install the radiator.
  26.  
  27. Install the heater hose to the engine.
  28.  
  29. Connect the accelerator, cruise control and detent cables at the injection pump.
  30.  
  31. Connect the power steering pump and reservoir.
  32.  
  33. Install the fan and the upper fan shroud.
  34.  
  35. Install the ground strap.
  36.  
  37. Connect the wiring to the rocker cover including the glow plug wires.
  38.  
  39. Connect the EGR/EPR solenoids, glow plug controller and temperature solenoid harness.
  40.  
  41. Connect the alternator wires and clips.
  42.  
  43. Connect the wiring at the injector pump.
  44.  
  45. Install the air cleaner.
  46.  
  47. Install the hood.
  48.  
  49. Connect the negative battery cable.
  50.  
  51. Install the proper quantity and grade of coolant.
  52.  
  53. Ensure that the crankcase has the proper grade and quantity of oil.
  54.  

 
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