Isuzu Ascender 2003-05

Oil Pump

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Inspection



Clean all parts of sludge, oil, and varnish by soaking in carburetor cleaner or cleaning solvent. Inspect for foreign material and determine the source of the foreign material. Inspect the oil pump housing and engine front cover for cracks, scoring, damaged threads and casting imperfections. Do not attempt to repair the oil pump housing. Replace the oil pump housing if damage is found. Inspect the oil pump gears for damage. Measure the inner oil pump gear tip clearance in several places.  Measure the outer oil pump gear tip clearance in several places. Measure the oil pump gear side clearance. Inspect the pressure regulator valve for scoring, burrs and sticking.

Click image to see an enlarged view

Fig. Oil pump inner inspection-4.2L



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Fig. Oil pump outer inspection-4.2L



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Fig. Oil pump assembly-5.3L

Inspect the pressure regulator valve spring for loss of tension or bending. Replace the pressure regulator spring if damaged. Inspect the oil pump pipe pickup tube and screen assembly for loose or bent conditions, broken wire mesh or screen. Inspect the O-ring seal at the base of the oil pump pickup tube for damage.

Removal & Installation



4.2L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Engine front cover
     
    Oil pump cover bolts
     
    Oil pump cover. Mark the inner and outer gears in relation to the pump housing.
     
    Inner and outer pump gears
     
    Oil pump pressure relief valve plug
     
    Oil pump pressure relief valve and spring
     

  4.  

To install:

  1. Install or connect the following:

    Oil pump pressure relief valve and spring
     
    Oil pump pressure relief valve plug. Tighten to 10 ft. lbs. (14 Nm).
     
    Oil pump outer and inner gears, as marked during removal
     
    Oil pump cover and bolts. Tighten the bolts to 89 inch lbs. (10 Nm).
     
    Front cover
     

  2.  

  1. Before servicing the vehicle, refer to the precautions section.
  2.  
  3. Remove or disconnect the following:

    Engine front cover
     
    Oil pump cover bolts
     
    Oil pump cover. Mark the inner and outer gears in relation to the pump housing.
     
    Inner and outer pump gears
     
    Oil pump pressure relief valve plug
     
    Oil pump pressure relief valve and spring
     

  4.  

To install:

  1. Install or connect the following:

    Oil pump pressure relief valve and spring
     
    Oil pump pressure relief valve plug. Tighten to 10 ft. lbs. (14 Nm).
     
    Oil pump outer and inner gears, as marked during removal
     
    Oil pump cover and bolts. Tighten the bolts to 89 inch lbs. (10 Nm).
     
    Front cover
     

  2.  

5.3L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Oil pan
     
    Engine front cover
     
    Oil pump screen bolt and nuts
     
    Oil pump screen with O-ring seal
     
    O-ring seal from the pump screen. Discard the O-ring seal.
     
    Remaining crankshaft oil deflector nuts
     
    Crankshaft oil deflector
     
    Oil pump bolts
     
    Oil pump
     

  4.  


NOTE
Do not let any dirt or debris into the oil pump or cap end.



Clean and inspect the oil pump.
 



Click image to see an enlarged view

Fig. Exploded view of the oil pump mounting-5.3L engine

To install:

  1. Align the splined surfaces of the crankshaft sprocket and the oil pump drive gear and install the oil pump.
  2.  
  3. Install or connect the following:

    Oil pump onto the crankshaft sprocket until the pump housing contacts the face of the engine block
     
    Oil pump bolts and tighten to 18 ft. lbs. (25 Nm)
     
    Crankshaft oil deflector and nuts until snug
     
    New oil pump screen O-ring seal into the oil pump screen, after lubricating with clean engine oil
     

  4.  


NOTE
Push the oil pump screen tube completely into the oil pump prior to tightening the bolt. Do not let the bolt pull the tube into the pump.

  1. Align the oil pump screen mounting brackets with the correct crankshaft bearing cap studs.

    Oil pump screen
     
    Oil pump screen bolts and nuts. Tighten the bolts to 106 inch lbs. (12 Nm) and the nuts to 18 ft. lbs. (25 Nm).
     
    Engine front cover
     
    Oil pan
     

  2.  

  1. Before servicing the vehicle, refer to the precautions section.
  2.  
  3. Remove or disconnect the following:
    NOTE
    Do not let any dirt or debris into the oil pump or cap end.



    Oil pan
     
    Engine front cover
     
    Oil pump screen bolt and nuts
     
    Oil pump screen with O-ring seal
     
    O-ring seal from the pump screen. Discard the O-ring seal.
     
    Remaining crankshaft oil deflector nuts
     
    Crankshaft oil deflector
     
    Oil pump bolts
     
    Oil pump
     



    Clean and inspect the oil pump.

    Click image to see an enlarged view

    Fig. Exploded view of the oil pump mounting-5.3L engine

     

  4.  

To install:

  1. Align the splined surfaces of the crankshaft sprocket and the oil pump drive gear and install the oil pump.
  2.  
  3. Install or connect the following:
    NOTE
    Push the oil pump screen tube completely into the oil pump prior to tightening the bolt. Do not let the bolt pull the tube into the pump.



    Oil pump onto the crankshaft sprocket until the pump housing contacts the face of the engine block
     
    Oil pump bolts and tighten to 18 ft. lbs. (25 Nm).
     
    Crankshaft oil deflector and nuts until snug
     
    New oil pump screen O-ring seal into the oil pump screen, after lubricating with clean engine oil
     

  4.  
  5. Align the oil pump screen mounting brackets with the correct crankshaft bearing cap studs.

    Oil pump screen
     
    Oil pump screen bolts and nuts. Tighten the bolts to 106 inch lbs. (12 Nm) and the nuts to 18 ft. lbs. (25 Nm).
     
    Engine front cover
     
    Oil pan
     

  6.  

 
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