GM Grand Am/Achieva/Calais/Skylark/Somerset 1985-98

Oil Pump

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REMOVAL & INSTALLATION



2.0L Engine
  1. Disconnect negative battery cable.
  2.  
  3. Remove the timing belt and crankshaft sprocket.
  4.  
  5. Remove the rear timing belt cover.
  6.  
  7. Detach the oil pressure sending unit connector.
  8.  
  9. Raise and safely support the front of the vehicle.
  10.  
  11. Drain the engine oil.
  12.  
  13. Remove the oil pan and oil filter.
  14.  
  15. Unfasten the oil pump mounting bolts, then remove the pump and pickup tube.
  16.  

To install:
  1. Prime the pump by pouring fresh oil into the pump intake and turning the driveshaft until oil comes out the pressure port. Repeat a few times until no air bubbles are present.
  2.  
  3. The installation is the reverse of the removal procedure. Use a new gasket and seal and tighten the oil pump bolts to 5 ft. lbs. (7 Nm). Use a new ring for the pickup tube.
  4.  
  5. Lower the vehicle.
  6.  
  7. Fill the crankcase with the proper oil.
  8.  
  9. Connect the negative battery cable, check the oil pressure and check for leaks.
  10.  

2.3L Engine

See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the front of the vehicle.
  4.  
  5. Drain the engine oil and remove the oil pan. For details, please refer to the procedure located in this section.
  6.  
  7. Unfasten the oil pump attaching bolts and nut. Next, remove the oil pump assembly, shims if equipped, and screen.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: Common view of the oil pump-2.3L engine

To install:
  1. With the oil pump assembly off the engine, remove 3 attaching 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 inch (0.254-0.457mm). When measuring, do not allow the crankshaft to move.
  8.  
  9. If equipped with shims, remove some to decrease clearance and add some 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. Tighten oil pump-to-block bolts 33 ft. lbs. (45 Nm).
  16.  
  17. Install the oil pan and lower the vehicle.
  18.  
  19. Fill the crankcase with the proper oil.
  20.  
  21. Connect the negative battery cable, check the oil pressure and check for leaks.
  22.  

2.4L Engine

See Figure 2

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the front of the vehicle securely on jackstands.
  4.  
  5. Remove the engine oil pan as described earlier in this section.
  6.  
  7. Remove the balance shaft chain cover and tensioner assembly.
  8.  
  9. Unbolt the oil pump cover and pull the pump from the engine
  10.  



Click image to see an enlarged view

Fig. Fig. 2: The oil pump is held on the engine with three bolts-2.4L engine

To install:
  1. Lubricate all internal parts with clean engine oil and fill all pump cavities with petroleum jelly.
  2.  
  3. Attach the oil pump and cover to the balance shaft housing. Tighten the pump bolts to the block and secure them to 106 inch lbs. (12 Nm).
  4.  
  5. Install the balance shaft chain tensioner.
    1. Adjust the balance shaft drive chain tension by increasing a 0.40 inch (1mm) BRASS feeler gage between the chain guide and chain.
    2.  

  6.  

A BRASS feeler gage needs to be used to ensure correct measurements are obtained. If a steel gauge is used, it will not bend to conform to the guide and will allow for incorrect measurements.

    1. Press the guide against the chain using about 3 lbs of force.
    2.  
    3. Tighten the chain tensioner fastener. Tighten the bolt to 115 inch lbs. (13 Nm).
    4.  
    5. Install a secure the balance chain cover. Tighten the nut and bolt to 115 inch lbs. (13 Nm).
    6.  

  1. Install the oil pan and gasket. Refer to the procedure earlier in this section.
  2.  
  3. Lower the vehicle.
  4.  
  5. Connect the negative battery cable.
  6.  
  7. Check the oil fluid level in the engine and fill as necessary.
  8.  
  9. Start the engine and listen for abnormal noises once the engine has warmed up.
  10.  

2.5L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the engine oil and remove the oil pan.
  4.  
  5. Remove the oil filter.
  6.  
  7. Remove the oil pump cover assembly.
  8.  
  9. Remove the gyrator pump gears.
  10.  


CAUTION
The pressure regulator valve spring is under pressure. Exercise caution when removing the pin or personal injury may result!

  1. Remove the pressure regulator pin, spring and valve.
  2.  

To install:
  1. Lubricate all internal parts with clean engine oil and fill all pump cavities with petroleum jelly.
  2.  
  3. Install the pressure regulator valve, spring and secure the pin.
  4.  
  5. Install the gyrator gears.
  6.  
  7. Install the pump cover and tighten the screws to 10 ft. lbs. (14 Nm).
  8.  
  9. Install the oil filter.
  10.  
  11. Install the oil pan.
  12.  
  13. Fill the crankcase with oil to specification.
  14.  
  15. Connect the negative battery cable, check the oil pressure and check for leaks.
  16.  

3.0L and 3.3L Engines

See Figures 3 and 4

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the timing chain front cover.
  4.  
  5. Raise and safely support the front of the vehicle securely on jackstands.
  6.  
  7. Drain the engine oil. Lower the vehicle.
  8.  
  9. Remove the oil filter adapter, the pressure regulator valve and the valve spring.
  10.  
  11. Remove the oil pump cover-to-oil pump screws and remove the cover.
  12.  
  13. Remove the oil pump gears.
  14.  



Click image to see an enlarged view

Fig. Fig. 3: Once the oil pan is removed, you can see the pump and screen assembly-3.0L engine



Click image to see an enlarged view

Fig. Fig. 4: View of the oil pump mounting-3.3L engine shown

To install:
  1. Lubricate the oil pump gears with clean engine oil.
  2.  
  3. Pack the pump cavity with petroleum jelly.
  4.  
  5. Install the oil pump cover screws using a new gasket and tighten to 97 inch lbs. (11 Nm).
  6.  
  7. Install the pressure regulator spring and valve.
  8.  
  9. Install the oil filter adaptor using a new gasket. Tighten the oil filter adapter-to-engine bolts to 30 ft. lbs. (41 Nm) for the 3.0L engine or 24 ft. lbs. (33 Nm) for the 3.3L engine.
  10.  
  11. Install the timing chain front cover to the engine.
  12.  
  13. Fill the crankcase with clean engine oil.
  14.  
  15. Connect the negative battery cable, check the oil pressure and check for leaks.
  16.  

3.1L Engine

See Figures 5 and 6

  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. For details, refer to the procedure located in this section.
  8.  
  9. Unfasten the crankshaft oil deflector bolts, then remove the crankshaft oil deflector.
  10.  
  11. Remove the oil pump retaining bolts, then remove the oil pump and pump driveshaft.
  12.  



Click image to see an enlarged view

Fig. Fig. 5: View of the oil pump and drive assembly mounting-3.1L engine

To install:
  1. Prime the oil pump.
  2.  
  3. Install the oil pump and pump driveshaft. Tighten the oil pump mounting bolts to 30 ft. lbs. (41 Nm).
  4.  



Click image to see an enlarged view

Fig. Fig. 6: Exploded view of the oil pump-3.1L engine

  1. Install the crankshaft oil deflector and mounting nuts. Tighten the mounting nuts to 18 ft. lbs. (25 Nm).
  2.  
  3. Install the oil pan. For details, please refer to the procedure located in this section.
  4.  
  5. Carefully lower the vehicle.
  6.  
  7. Fill the crankcase to the correct level with oil.
  8.  
  9. Start the engine, check the oil pressure and check for leaks.
  10.  

 
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