GM Metro/Sprint 1985-1993 Repair Guide

Oil Pump

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REMOVAL



See Figures 1 and 2



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Fig. Fig. 1: Oil pump assembly



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Fig. Fig. 2: Location of oil pump mounting bolts

  1. Remove the negative battery cable.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Drain the engine oil.
  6.  
  7. Remove the water pump belt, pulley, alternator, alternator bracket and air conditioning mounting bracket, if equipped.
  8.  
  9. Remove the crankshaft pulley, timing belt outside cover, timing belt and tensioner.
  10.  
  11. Disconnect the engine oil level gauge.
  12.  
  13. Remove the crankshaft timing belt gear and timing belt guide. With the crankshaft locked, remove the crankshaft timing belt pulley bolt.
  14.  
  15. Remove the oil pan bolts, oil pan, oil strainer fixing bolt and the oil strainer assembly.
  16.  
  17. Remove the oil pump bolts and the oil pump assembly.
  18.  

INSPECTION



See Figures 3 and 4



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Fig. Fig. 3: Measuring oil pump rotor radial clearance



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Fig. Fig. 4: Measuring oil pump rotor side clearance

  1. Inspect the oil seal lip for damage and replace as necessary.
  2.  
  3. Inspect the outer and inner rotors, rotor plate and oil pump body for excessive wear or damage. Replace as necessary.
  4.  
  5. Measure the radial clearance between the outer rotor and case using a feeler gauge. If clearance exceeds 0.0122 in. (0.310mm), replace the outer rotor or case.
  6.  
  7. Measure the side clearance using a straight edge and feeler gauge. If clearance exceeds 0.0059 in. (0.15 mm), replace the oil pump case.
  8.  

OVERHAUL



  1. Remove the bolt and guide tube from the oil pump. Discard the seal.
  2.  
  3. Remove the screws and rotor plate from the pump body.
  4.  
  5. Remove the outer and inner rotors from the pump body.
  6.  
  7. Inspect the pump and rotors. Measure clearances and replace components as necessary.
  8.  
  9. Clean and dry all disassembled parts.
  10.  
  11. Apply a thin coat of engine oil to inner and outer rotors, oil seal lip portion and inside surfaces of oil pump body.
  12.  
  13. Assemble outer and inner rotors to pump body.
  14.  
  15. Install rotor plate and secure with screws.
  16.  
  17. Check to be sure that rotors turn freely by hand.
  18.  
  19. Install guide seal and guide tube to oil pump. Tighten bolt to 97 inch lbs.. (11 Nm).
  20.  

INSTALLATION



  1. Clean the gasket mating surfaces thoroughly.
  2.  
  3. Lubricate the oil pump with fresh engine oil.
  4.  
  5. Using new gaskets and sealant, install the oil pump on the engine.
  6.  

Take care not to damage the front seal on the crankshaft snout.

  1. Apply Loctite® pipe sealant or equivalent to the oil pump bolts and install. Tighten to 97 inch lbs.. (11 Nm).
  2.  

After tightening the oil pump seal may bulge out. If it does, trim the edge with a sharp knife, making sure the edge is smooth and flush with the cylinder block.

  1. Install the rubber seal between the oil pump and coolant pump.
  2.  
  3. Install the crankshaft timing belt gear and timing belt guide. With the crankshaft locked, tighten the pulley bolt to 81 ft. lbs.. (110 Nm).
  4.  
  5. Install the engine oil level gauge.
  6.  
  7. Install the oil strainer and oil pan.
  8.  
  9. Install the timing belt, tensioner and outside cover.
  10.  
  11. Install the water pump belt, pulley, alternator, alternator bracket and air conditioning mounting bracket, if equipped.
  12.  
  13. Lower the vehicle and fill the engine with oil.
  14.  
  15. Connect the negative battery cable, start the engine and check for proper oil pressure. Check for leaks.
  16.  

Crankshaft PulleyREMOVAL and INSTALLATION

See Figure 5



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Fig. Fig. 5: Crankshaft pulley and bolts

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Remove the clips and right side splash shield.
  6.  
  7. Remove the lower generator cover plate.
  8.  
  9. Remove the alternator and, as required, air conditioner drive belt.
  10.  

It is not necessary to remove the crankshaft timing gear bolt in the center of the pulley to remove the pulley.

  1. Remove the crankshaft pulley bolts and crankshaft pulley.
  2.  

To install:
  1. Install the crankshaft pulley. Fit the keyway on the pulley to the key on crankshaft timing gear. Tighten pulley bolts to 97 ft. lbs.. (11 Nm).
  2.  
  3. Install the generator drive belt and lower generator cover plate. Tighten cover plate bolts to 89 inch lbs.. (10 Nm).
  4.  
  5. Install the air conditioner drive belt, as required.
  6.  
  7. Install the right side splash shield and secure with clips.
  8.  
  9. Lower the vehicle and connect the negative battery cable.
  10.  

 
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