GM Lumina/Grand Prix/Cutlass Supreme/Regal 1988-1996

Oil Pump

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REMOVAL




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 your 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.

2.2L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle, then drain the engine oil.
  4.  
  5. Remove the oil pan, as outlined earlier in this section.
  6.  
  7. Unfasten the pump retaining bolt from the rear main bearing cap, then remove the pump and extension shaft.
  8.  
  9. Remove the extension shaft and retainer, but be very careful NOT to crack the retainer.
  10.  

2.3L Engine

See Figure 1



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Fig. Fig. 1: Oil pan-to-block assembly mounting-2.3L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Drain the engine oil and remove the oil pan.
  6.  
  7. Unfasten the oil pump retaining bolts and nut.
  8.  
  9. Remove the oil pump assembly, shims, if equipped, and screen.
  10.  

2.5L, 2.8L, 3.1L and 3.4L Engines

See Figures 2, 3 and 4



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Fig. Fig. 2: Exploded view of the oil pump assembly-2.5L engine



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Fig. Fig. 3: Oil pump mounting-2.8L and 3.1L engines



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Fig. Fig. 4: View of the oil pump assembly mounting-3.4L engine

On the 2.5L engine, the force balancer assembly does not have to be removed to service the oil pump or pressure regulator assemblies.

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Drain the engine oil into a suitable container.
  6.  
  7. Remove the oil pan, as outlined earlier in this section.
  8.  
  9. On 3.4L engine, it will be necessary to remove the oil pan baffle by extracting the nuts and rotating the oil pick up tube out of the way.
  10.  
  11. Unfasten the oil pump retaining bolts and remove the oil pump and pump driveshaft.
  12.  

3.8L Engine

See Figure 5



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Fig. Fig. 5: Exploded view of the oil pump assembly-3.8L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Drain the engine oil.
  6.  
  7. Remove the front cover assembly.
  8.  
  9. Remove the oil filter adapter, pressure regulator valve and spring.
  10.  
  11. Remove the oil pump cover attaching screws and remove the cover.
  12.  
  13. Remove the oil pump gears.
  14.  

INSPECTION



2.2L Engine
  1. Inspect all components carefully for physical damage of any type and replace worn parts.
  2.  
  3. Check the gear pocket depth. The specification is 1.195-1.198 In. (30.36-30.44mm).
  4.  
  5. Check the gear pocket diameter. The specification is 1.503-1.506 in. (38.18-38.25mm).
  6.  
  7. Check the gear length. The measurement is 1.199-1.200 in. (30.45-30.48mm).
  8.  
  9. Check the outer gear diameter clearance. The specificaiton is 1.498-1.500 in. (38.05-38.10mm).
  10.  
  11. Replace the oil pump assembly if any specification is out of range.
  12.  

2.3L Engine
  1. Check the gerotor cavity depth. The specification is 0.674-0.676 in. (17.11-17.16mm).
  2.  
  3. Check the gerotor cavity diameter. The specification is 2.127-2.129 in. (53.95-54.00mm).
  4.  
  5. Check the inner gerotor tip clearance. The maximum clearance is 0.006 in. (0.15mm).
  6.  
  7. Check the outer gerotor diameter clearance. The specification is 0.010-0.014 in. (0.254-0.354mm).
  8.  
  9. Replace the oil pump assembly if any specification is out of range.
  10.  

2.5L Engine
  1. Inspect all components carefully for physical damage of any type and replace worn parts.
  2.  
  3. Check the gerotor cavity depth. The specification for 1988 is 0.995-0.998 in. (25.27-25.35mm). The specification for 1989-92 is 0.514-0.516 in. (13.05-13.10mm).
  4.  
  5. Check the gear lash. The specification is 0.009-0.015 in. (0.23-0.38mm).
  6.  
  7. Check the clearance of both gears. The maximum clearance is 0.004 in. (0.10mm).
  8.  
  9. Replace the oil pump assembly if any specification is out of range. (0.10mm).
  10.  

2.8L, 3.1L and 3.4L Engines
  1. Inspect all components carefully for physical damage of any type and replace worn parts.
  2.  
  3. Check the gear pocket depth. The specification is 1.195-1.198 in. (30.36-30.44mm).
  4.  
  5. Check the gear pocket diameter. The specification is 1.503-1.506 in. (38.18-38.25mm).
  6.  
  7. Check the gear length. The measurement is 1.199-1.200 in. (30.45-30.48mm).
  8.  
  9. Check the outer gear diameter clearance. The specification is 1.498-1.500 in. (38.05-38.10mm).
  10.  
  11. The pressure regulator valve-to-bore clearance should be 0.0015-0.0035 in. (0.038mm-0.089mm).
  12.  
  13. Replace the oil pump assembly if any specification is out of range.
  14.  

3.8L Engine
  1. Inspect all components carefully for physical damage of any type and replace worn parts.
  2.  
  3. The inner tip clearance should be 0.006 in. (0.15mm).
  4.  
  5. The outer gear diameter clearance should be 0.008-0.015 in. (0.20-0.38mm).
  6.  
  7. The gear end clearance or the drop in the housing should be 0.001-0.0035 in. (0.025-0.089mm).
  8.  
  9. The pressure regulator valve-to-bore clearance should be 0.0015-0.003 in. (0.038-0.076mm).
  10.  
  11. Replace the oil pump assembly if any specification is out of range.
  12.  

INSTALLATION



2.2L Engine
  1. Remove oil pump from block, fill the cavity with petroleum jelly and reinstall driven gear cover assembly to pump. Tighten the bolts to 89 inch lbs. (10 Nm).
  2.  
  3. Heat the extension shaft in hot water before assembling the extension shaft.
  4.  
  5. Attach the extension to the oil pump. Make sure the retainer does not crack during installation.
  6.  
  7. Install the pump-to-rear bearing cap, then install the retaining bolt. Tighten the bolt to 32 ft. lbs. (43 Nm).
  8.  
  9. Install the oil pan, as outlined earlier in this section.
  10.  
  11. Carefully lower the vehicle, then fill the crankcase with the proper type and amount of engine oil.
  12.  
  13. Connect the negative battery cable, then start the engine and check for proper operation.
  14.  

2.3L Engine
  1. With oil pump assembly OFF engine, remove 3 retaining bolts and separate the driven gear cover and screen assembly from the oil pump.
  2.  
  3. Install the oil pump on the block using the original shims, if equipped. Tighten the bolts to 33 ft. lbs. (45 Nm).
  4.  
  5. Mount a dial indicator assembly to measure backlash between oil pump to drive gear.
  6.  
  7. Record oil pump drive to driven gear backlash. Proper backlash is 0.010-0.018 in. (0.25-0.45mm). When measuring, do not allow the crankshaft to move.
  8.  
  9. If equipped with shims, remove shims to decrease clearance and add shims to increase clearance. If no shims were present, replace the assembly if proper backlash cannot be obtained.
  10.  
  11. When the proper clearance is reached, rotate crankshaft 1 / 2 turn and recheck clearance.
  12.  
  13. Remove oil pump from block, fill the cavity with petroleum jelly and reinstall driven gear cover and screen assembly to pump. Tighten the bolts to 106 inch lbs. (13 Nm).
  14.  
  15. Reinstall the pump assembly to the block. Torque oil pump-to-block bolts 33 ft. lbs. (45 Nm).
  16.  
  17. Install the oil pan.
  18.  
  19. Fill the crankcase with the proper oil.
  20.  
  21. Start the engine, check the oil pressure and check for leaks. Do not run the engine without measurable oil pressure.
  22.  

2.5L, 2.8L, 3.1L and 3.4L Engines
  1. Pack the pump with petroleum jelly.
  2.  
  3. Install the oil pump and pump driveshaft. Tighten the oil pump mounting bolts to 30 ft. lbs. (41 Nm) for the 2.8L and 3.1L engines, 40 ft. lbs. (54 Nm) for 3.4L engine or to 89 inch lbs. (10 Nm) for 2.5L engine.
  4.  
  5. Install oil pan baffle, if equipped, and tighten nuts to 18 ft. lbs. (25 Nm).
  6.  
  7. Install the oil pan, then carefully lower the vehicle.
  8.  
  9. Fill the crankcase to the correct level with oil.
  10.  
  11. Connect the negative battery cable, then start the engine, check the oil pressure and check for leaks. Do not run the engine without measurable oil pressure.
  12.  

3.8L Engine
  1. Lubricate the gears with petroleum jelly and install the gears into the housing.
  2.  
  3. Pack the gear cavity with petroleum jelly after the gears have been installed in the housing.
  4.  
  5. Install the oil pump cover and screws and tighten to 97 inch lbs.
  6.  
  7. Install the oil filter adapter with new gasket, pressure regulator valve and spring.
  8.  
  9. Install the front cover assembly.
  10.  
  11. Fill with clean engine oil. Start the engine, check the oil pressure and check for leaks. Do not run the engine without measurable oil pressure.
  12.  

 
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