Astro, Safari 1997-2005

Oil Pump

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Overhaul




CAUTION
Wear safety glasses in order to avoid eye damage.

  1. Clean the oil pump components in cleaning solvent.
  2.  
  3. Dry the components with compressed air.
  4.  
  5. Inspect the oil pump for the following conditions:
    1. Scoring on the top of gears (1)
    2.  
    3. Damaged gears (2) for chipping, galling or wear.
    4.  
    5. Scoring, damage or casting imperfections to the body (3)
    6.  
    7. Damaged or scored gear shafts (4) or (5)
    8.  
    9. Damaged bolt hole threads
    10.  
    11. Worn oil pump drive shaft bore
    12.  
    13. Damaged or sticking oil pump pressure relief valve. Minor imperfections may be removed with a fine oil stone.
    14.  
    15. Collapsed or broken oil pump pressure relief valve spring

      Click image to see an enlarged view

      Fig. Oil pump exploded view-4.3L engine

    16.  

  6.  
  7. If the oil pump is to be reused, install a NEW oil pump pressure relief valve spring.
  8.  
  9. During oil pump installation, install a NEW oil pump drive shaft retainer.
  10.  

Removal & Installation



  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove oil pan.
  4.  
  5. Remove oil pump bolt, if necessary.
  6.  
  7. Remove oil pump and the pickup tube/shaft, if equipped.
    NOTE
    Be careful not to crack the retainer.



    Click image to see an enlarged view

    Fig. Exploded view of the oil pump-2002 model shown, others similar

  8.  

To install:

  1. Ensure that the pump pickup tube is tight in the pump body. If the tube should come loose, oil pressure will be lost and oil starvation will occur. If the pickup tube is loose it should be replaced.
  2.  
  3. If the pump has been disassembled and is being replaced or for any reason oil has been removed, it must be primed. It can either be filled with oil before installing the cover plate and oil kept within the pump during handling or the entire pump cavity can be filled with petroleum jelly.
    WARNING
    If the pump is not primed, the engine could be damaged upon start up.

  4.  
  5. Install oil pump by aligning the pump shaft with the distributor drive gear as necessary. Tighten oil pump/pickup tube retainer(s) to 65 ft. lbs. (90 Nm).
    NOTE
    If the oil pump does not build up oil pressure almost immediately, remove the pan and check for a loose oil pump-to-pickup tube attachment. If necessary dismantle the pump and pack the pump cavity with petroleum jelly.

  6.  
  7. Install oil pan.
  8.  
  9. Refill the crankcase.
  10.  
  11. Disable the ignition system; crank engine for approximately 10 seconds to aid in priming the oil pump and reducing the risk of engine damage.
    WARNING
    Running the engine without measurable oil pressure will cause extensive damage.

  12.  

 
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