GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Water Pump

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DIAGNOSIS



Check the water pump operation by running the engine while squeezing the upper radiator hose. When the engine warms (thermostat opens) a pressure surge should be felt. Check for a plugged vent hole at the pump snout.

REMOVAL & INSTALLATION



See Figures 1 through 8

1.9L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the front of the vehicle safely using jackstands.
  4.  
  5. Remove the lower fan shroud/cover for access, then drain the engine cooling system.
  6.  
  7. If not equipped with A/C, remove the fan-to-water pump nuts and the fan from the vehicle. In most cases, it is easier to loosen the components and remove the drive belts before attempting to remove the pulley.
  8.  
  9. If equipped with A/C:
    1. Loosen the air pump and alternator adjusting bolts, pivot them toward the engine and remove the drive belt(s).
    2.  
    3. Remove the fan-to-water pump nuts and the fan (with the fan and air pump drive pulley) from the vehicle.
    4.  
    5. Remove the fan set plate/pulley-to-water pump bolts, then remove the set plate and the pulley.
    6.  

  10.  
  11. Disconnect the coolant hoses at the water pump.
  12.  
  13. Remove the water pump-to-engine bolts and the water pump from the engine.
  14.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces.
  2.  
  3. Install the water pump to the engine using a new gasket and sealant, then tighten the water pump bolts to 15-22 ft. lbs. (20-30 NM).
  4.  
  5. Connect the coolant hoses to the water pump.
  6.  
  7. If equipped with A/C, install the fan set plate/pulley to the water pump, then install the fan. Install the air pump and alternator drive belts, then adjust the belt tension.
  8.  
  9. If not equipped with A/C, install the fan assembly to the vehicle.
  10.  
  11. Make sure the radiator petcock is closed, then install the lower fan shroud/cover.
  12.  
  13. Remove the jackstands and carefully lower the vehicle.
  14.  
  15. Connect the negative battery cable and properly refill the engine cooling system.
  16.  
  17. Run the engine and check for leaks.
  18.  



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Fig. Fig. 1: Loosen and remove the drive belts from the water pump pulley



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Fig. Fig. 2: Some vehicles (like this early 2.8L engine) use a spacer between the fan and water pump pulley



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Fig. Fig. 3: Remove the pulley from the pump hub



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Fig. Fig. 4: Loosen and remove all of the water pump retaining bolts



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Fig. Fig. 5: For some engines it may be easier to remove the pump from the engine with a hose still attached



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Fig. Fig. 6: This hose was easier to disconnect once the pump was removed



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Fig. Fig. 7: Carefully clean all traces of gasket and sealant from the front of the engine



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Fig. Fig. 8: If the old pump is to be reinstalled, clean the gasket mating surface of the pump as well

2.0L Engine

See Figure 9

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the engine cooling system.
  4.  
  5. Remove the upper fan shroud and all of the necessary drive belts.
  6.  
  7. Disconnect the radiator and heater hoses from the water pump.
  8.  
  9. Remove the water pump-to-engine bolts, then remove the water pump from the vehicle.
  10.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces.
  2.  



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Fig. Fig. 9: Water pump mounting-2.0L engine

  1. Install the water pump to the engine using a new gasket and sealant, then tighten the water pump bolts to 15-22 ft. lbs. (20-30 NM).
  2.  
  3. Connect the radiator and heater hoses to the water pump.
  4.  
  5. Install the necessary drive belts, then install the fan shroud.
  6.  
  7. Connect the negative battery cable and properly refill the engine cooling system.
  8.  
  9. Run the engine and check for leaks.
  10.  

2.2L Diesel Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the power steering reservoir, then remove the upper fan shroud.
  4.  
  5. Drain the engine cooling system.
  6.  
  7. Remove the drive belts, the fan and, if equipped, the A/C compressor (move it aside with the lines attached).
  8.  
  9. Disconnect the radiator pipe at the front cover.
  10.  
  11. Disconnect the radiator and heater hoses from the right-side of the water pump
  12.  
  13. Disconnect the PCV valve from the rocker cover. Remove the air cleaner and the heater pipe from the intake manifold.
  14.  
  15. Disconnect the heater hose from the left-side of the water pump, then the alternator brace.
  16.  
  17. Remove the water pump-to-engine bolts and the water pump from the engine.
  18.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces.
  2.  
  3. Install the water pump to the engine using a new gasket, then tighten the water pump-to-engine bolts to 10-17 ft. lbs. (14-23 Nm).
  4.  
  5. Install the alternator brace, then connect the heater hose to the left-side of the water pump.
  6.  
  7. Install the air cleaner and the heater pipe to the intake manifold, then connect the PCV valve to the rocker cover.
  8.  
  9. Connect the radiator and heater hoses to the right-side of the water pump
  10.  
  11. Connect the radiator pipe to the front cover.
  12.  
  13. Reposition and secure the A/C compressor (if equipped), then install the drive belts and the fan.
  14.  
  15. Install the upper fan shroud, then connect the power steering reservoir.
  16.  
  17. Connect the negative battery cable, then properly refill the engine cooling system and check for leaks.
  18.  

2.5L, 2.8L and 4.3L Gasoline Engines

See Figures 10, 11, 12 and 13



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Fig. Fig. 10: Water pump mounting-2.5L engine



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Fig. Fig. 11: Applying sealant to a water pump on an early model 2.8L engine



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Fig. Fig. 12: Water pump mounting-2.8L engine (note torque specifications are for 1993 engines only)



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Fig. Fig. 13: Water pump mounting-4.3L engine (note that stud locations may vary)

  1. Disconnect the negative battery cable, then drain the engine cooling system.
  2.  
  3. Relieve the belt tension, then remove the accessory drive belts or the serpentine drive belt, as applicable.
  4.  
  5. Remove the upper fan shroud, then remove the fan or fan and clutch assembly, as applicable.
  6.  
  7. Remove the water pump pulley.
  8.  
  9. Loosen the clamp and disconnect the coolant hose(s) from the water pump.
  10.  

On some engines, such as the heater hose on the early 2.8L, removal may be easier if the hose is left attached until the pump is free from the block. Once the pump is removed from the engine, the pump may be pulled (giving a better grip and greater leverage) from the tight hose connection.

  1. Remove the retainers, then remove the water pump from the engine. Note the positions of all retainers as some engines will utilize different length fasteners in different locations and/or bolts and studs in different locations.
  2.  

To install:
  1. Using a putty knife, carefully clean the gasket mounting surfaces.
  2.  

The water pumps on some of the earlier engines covered by this manual (early 2.8L's and 2.5L's for example) may have been installed using sealer only, no gasket, at the factory. If a gasket is supplied with the replacement part, it should be used. Otherwise, a1/8in. bead of RTV sealer should be used around the sealing surface of the pump.

  1. Apply 1052080 or an equivalent sealant to the threads of the water pump retainers. Install the water pump to the engine using a new gasket, then thread the retainers in order to hold it in position.
  2.  
  3. Tighten the water pump retainers to specification:
    1. For the 2.5L engine, tighten the water pump-to-engine retainers to 17 ft. lbs. (23 Nm).
    2.  
    3. For the 2.8L engine, tighten the retainers to 22 ft. lbs. (30 Nm) for all vehicles through 1992 or to 15 ft. lbs. (21 Nm) and 89 inch lbs. (10 Nm) depending on fastener location for 1993 vehicles. The central 3 lower bolts are tightened to the inch lbs. specification. Please refer to the illustration for clarification.
    4.  
    5. For the 4.3L engine, tighten the bolts and studs to 30 ft. lbs. (41 Nm).
    6.  

  4.  
  5. Connect the coolant hose(s) and secure using the retaining clamp(s).
  6.  
  7. Install the water pump pulley, then install the fan or fan and clutch assembly.
  8.  
  9. If equipped with a serpentine drive belt, position the belt over the pulleys, then carefully allow the tensioner back into contact with the belt.
  10.  
  11. If equipped with V-belts, install the accessory drive belts and adjust the tension.
  12.  
  13. Install the upper fan shroud, then connect the negative battery cable.
  14.  
  15. Properly refill the engine cooling system, then run the engine and check for leaks.
  16.  

 
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