Avalanche, Sierra, Silverado, C&K Series, 1999-2005

Oil Pump 1

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Inspection



4.3L Engine

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of the oil pump-4.3L engines

  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:

    Scoring on the top of the gears (1)
     
    Damaged gears (2) for the following:
     
    Chipping
     
    Galling
     
    Wear
     
    Scoring, damage or casting imperfections to the body (3)
     
    Damaged or scored gear shaft (4)
     
    Damaged or scored gear shaft (5)
     
    Damaged bolt hole threads
     
    Worn oil pump driveshaft bore
     
    Damaged or sticking oil pump pressure relief valve Minor imperfections may be removed with a fine oil stone.
     
    Collapsed or broken oil pump pressure relief valve spring
     
    If the oil pump is to be reused, install a NEW oil pump pressure relief valve spring.
     
    During oil pump installation, install a NEW oil pump driveshaft retainer.
     

  6.  


CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of the oil pump-4.3L engines

  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:

    Scoring on the top of the gears (1)
     
    Damaged gears (2) for the following:
     
    Chipping
     
    Galling
     
    Wear
     
    Scoring, damage or casting imperfections to the body (3)
     
    Damaged or scored gear shaft (4)
     
    Damaged or scored gear shaft (5)
     
    Damaged bolt hole threads
     
    Worn oil pump driveshaft bore
     
    Damaged or sticking oil pump pressure relief valve Minor imperfections may be removed with a fine oil stone.
     
    Collapsed or broken oil pump pressure relief valve spring
     
    If the oil pump is to be reused, install a NEW oil pump pressure relief valve spring.
     
    During oil pump installation, install a NEW oil pump driveshaft retainer.
     

  6.  

4.8L, 5.3L & 6.0L Engines

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of oil pump-4.8L, 5.3L and 6.0L engines


NOTE
The internal parts of the oil pump assembly are not serviced separately, excluding the spring. If the oil pump components are worn or damaged, replace the oil pump as an assembly.


NOTE
The oil pump pipe and screen are to be serviced as an assembly. Do not attempt to repair the wire mesh portion of the pump and screen assembly.

  1. Clean the parts in solvent.
  2.  
  3. Dry the parts with compressed air.

    Inspect the oil pump housing (413) and the cover (409) for cracks, excessive wear, scoring, or casting imperfections.
     
    Inspect the oil pump housing-to-engine block oil gallery surface for scratches or gouging.
     
    Inspect the oil pump housing for damaged bolt hole threads.
     
    Inspect the relief valve plug (416) and plug bore for damaged threads.
     
    Inspect the oil pump internal oil passages for restrictions.
     
    Inspect the drive gear (410) and driven gear (412) for chipping, galling or wear. Minor burrs or imperfections on the gears may be removed with a fine oil stone.
     
    Inspect the drive gear splines for excessive wear.
     
    Inspect the pressure relief valve (414) and bore for scoring or wear. The valve must move freely in the bore with no restrictions.
     
    Inspect the oil pump screen for debris or restrictions.
     
    Inspect the oil pump screen for broken or loose wire mesh.
     

  4.  

4.8L, 5.3L, 6.0L & 6.2L Engines

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of oil pump-4.8L, 5.3L, 6.0L and 6.2L engines


NOTE
The internal parts of the oil pump assembly are not serviced separately, excluding the spring. If the oil pump components are worn or damaged, replace the oil pump as an assembly.


NOTE
The oil pump pipe and screen are to be serviced as an assembly. Do not attempt to repair the wire mesh portion of the pump and screen assembly.

  1. Clean the parts in solvent.
  2.  
  3. Dry the parts with compressed air.

    Inspect the oil pump housing (413) and the cover (409) for cracks, excessive wear, scoring, or casting imperfections.
     
    Inspect the oil pump housing-to-engine block oil gallery surface for scratches or gouging.
     
    Inspect the oil pump housing for damaged bolt hole threads.
     
    Inspect the relief valve plug (416) and plug bore for damaged threads.
     
    Inspect the oil pump internal oil passages for restrictions.
     
    Inspect the drive gear (410) and driven gear (412) for chipping, galling or wear. Minor burrs or imperfections on the gears may be removed with a fine oil stone.
     
    Inspect the drive gear splines for excessive wear.
     
    Inspect the pressure relief valve (414) and bore for scoring or wear. The valve must move freely in the bore with no restrictions.
     
    Inspect the oil pump screen for debris or restrictions.
     
    Inspect the oil pump screen for broken or loose wire mesh.
     

  4.  

6.6L Engine

CAUTION
Wear safety glasses in order to avoid eye damage.

  1. Remove the oil pump gear cover bolts and oil pump gear cover.
  2.  
  3. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing. The production clearance is 0.005-0.009 inch) (0.125-0.221 mm) and the service limit is 0.009 inch (0.221 mm).

    Click image to see an enlarged view

    Fig. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing-6.6L engines

  4.  
  5. Replace the oil pump assembly if the clearance exceeds the service limit.
  6.  
  7. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover. The production clearance is 0.003-0.004 inch (0.064-0.109 mm) and the service limit is 0.004 inch (0.109 mm).

    Click image to see an enlarged view

    Fig. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover-6.6L engines

  8.  
  9. Replace the oil pump assembly if the clearance exceeds the service limit.
  10.  
  11. Calculate the driven gear shaft to bushing clearance.
    1. Measure the driven gear shaft outside diameter. The production specification is (0.785-0.786 inch (19.947-19.960 mm) and the service limit is 0.782 inch (19.86 mm).
    2.  
    3. Measure the driven gear bushing inside diameter. The production value is 0.787 inch (20 mm).
    4.  
    5. Calculate the driven gear shaft to bushing clearance. The service limit is 0.006 inch (0.14 mm)
    6.  

  12.  
  13. Replace the oil pump assembly if the clearance exceeds the service limit.

    Click image to see an enlarged view

    Fig. Measuring driven gear shaft and bushing-6.6L engines

  14.  
  15. Install the oil pump gear cover to the oil pump assembly.
  16.  
  17. Install the oil pump gear cover bolts.
    1. Tighten the oil pump gear cover bolts to 15 ft. lbs. (21 Nm).
    2.  

  18.  


CAUTION
Wear safety glasses in order to avoid eye damage.

  1. Remove the oil pump gear cover bolts and oil pump gear cover.
  2.  
  3. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing. The production clearance is 0.005-0.009 inch) (0.125-0.221 mm) and the service limit is 0.009 inch (0.221 mm).

    Click image to see an enlarged view

    Fig. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing-6.6L engines

  4.  
  5. Replace the oil pump assembly if the clearance exceeds the service limit.
  6.  
  7. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover. The production clearance is 0.003-0.004 inch (0.064-0.109 mm) and the service limit is 0.004 inch (0.109 mm).

    Click image to see an enlarged view

    Fig. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover-6.6L engines

  8.  
  9. Replace the oil pump assembly if the clearance exceeds the service limit.
  10.  
  11. Calculate the driven gear shaft to bushing clearance.
    1. Measure the driven gear shaft outside diameter. The production specification is (0.785-0.786 inch (19.947-19.960 mm) and the service limit is 0.782 inch (19.86 mm).
    2.  
    3. Measure the driven gear bushing inside diameter. The production value is 0.787 inch (20 mm).
    4.  
    5. Calculate the driven gear shaft to bushing clearance. The service limit is 0.006 inch (0.14 mm)
    6.  

  12.  
  13. Replace the oil pump assembly if the clearance exceeds the service limit.

    Click image to see an enlarged view

    Fig. Measuring driven gear shaft and bushing-6.6L engines

  14.  
  15. Install the oil pump gear cover to the oil pump assembly.
  16.  
  17. Install the oil pump gear cover bolts.
    1. Tighten the oil pump gear cover bolts to 15 ft. lbs. (21 Nm).
    2.  

  18.  

8.1L Engine

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of oil pump-8.1L engines

  1. Clean the oil pump components in cleaning solvent.
  2.  
  3. Dry the components with compressed air.
  4.  
  5. Inspect the gears for the following:

    Scoring
     
    Chipping
     
    Galling
     
    Excessive wear
     

  6.  
  7. Inspect the oil pump housing for the following:

    Damaged bolt hole threads
     
    Worn oil pump driveshaft bore
     
    Scoring or excessive wear within the housing
     
    Worn driven gear shaft
     

  8.  
  9. Inspect for a collapsed pressure relief valve spring.
  10.  
  11. Inspect the pressure relief valve for scoring or wear. The valve should move freely within the bore of the housing.
  12.  


CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of oil pump-8.1L engines

  1. Clean the oil pump components in cleaning solvent.
  2.  
  3. Dry the components with compressed air.
  4.  
  5. Inspect the gears (427, 428) for the following:

    Scoring
     
    Chipping
     
    Galling
     
    Excessive wear
     

  6.  
  7. Inspect the oil pump housing for the following:

    Damaged bolt hole threads
     
    Worn oil pump driveshaft bore
     
    Scoring or excessive wear within the housing
     
    Worn driven gear shaft
     

  8.  
  9. Inspect for a collapsed pressure relief valve spring.
  10.  
  11. Inspect the pressure relief valve for scoring or wear. The valve should move freely within the bore of the housing.
  12.  

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.

    Click image to see an enlarged view

    Fig. Typical oil pump-See text for parts identification

  4.  
  5. Inspect the oil pump for the following conditions:
    1. Scoring on the top of the gears (1)
    2.  
    3. Damaged gears (2) for the following:

      Chipping
       
      Galling
       
      Wear
       

    4.  
    5. Scoring, damage or casting imperfections to the body (3)
    6.  
    7. Damaged or scored gear shaft (4)
    8.  
    9. Damaged bolt hole threads
    10.  
    11. Worn oil pump driveshaft 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
    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 driveshaft retainer.
  10.  

4.3L, 5.0L, 5.7L, 6.5 And 7.4 Engines

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view oil pump

  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:

    Scoring on the top of the gears (1)
     
    Damaged gears (2) for the following:
     
    Chipping
     
    Galling
     
    Wear
     
    Scoring, damage or casting imperfections to the body (3)
     
    Damaged or scored gear shaft (4)
     
    Damaged or scored gear shaft (5)
     
    Damaged bolt hole threads
     
    Worn oil pump driveshaft bore
     
    Damaged or sticking oil pump pressure relief valve Minor imperfections may be removed with a fine oil stone.
     
    Collapsed or broken oil pump pressure relief valve spring
     
    If the oil pump is to be reused, install a NEW oil pump pressure relief valve spring.
     
    During oil pump installation, install a NEW oil pump driveshaft retainer.
     

  6.  

4.8L, 5.3L And 6.0L Engines

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of oil pump-4.8L, 5.3L and 6.0L engines


NOTE
The internal parts of the oil pump assembly are not serviced separately, excluding the spring. If the oil pump components are worn or damaged, replace the oil pump as an assembly.


NOTE
The oil pump pipe and screen are to be serviced as an assembly. Do not attempt to repair the wire mesh portion of the pump and screen assembly.

  1. Clean the parts in solvent.
  2.  
  3. Dry the parts with compressed air.

    Inspect the oil pump housing (413) and the cover (409) for cracks, excessive wear, scoring, or casting imperfections.
     
    Inspect the oil pump housing-to-engine block oil gallery surface for scratches or gouging.
     
    Inspect the oil pump housing for damaged bolt hole threads.
     
    Inspect the relief valve plug (416) and plug bore for damaged threads.
     
    Inspect the oil pump internal oil passages for restrictions.
     
    Inspect the drive gear (410) and driven gear (412) for chipping, galling or wear. Minor burrs or imperfections on the gears may be removed with a fine oil stone.
     
    Inspect the drive gear splines for excessive wear.
     
    Inspect the pressure relief valve (414) and bore for scoring or wear. The valve must move freely in the bore with no restrictions.
     
    Inspect the oil pump screen for debris or restrictions.
     
    Inspect the oil pump screen for broken or loose wire mesh.
     

  4.  

6.6L Engine

CAUTION
Wear safety glasses in order to avoid eye damage.

  1. Remove the oil pump gear cover bolts and oil pump gear cover.
  2.  
  3. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing. The production clearance is 0.005-0.009 inch) (0.125-0.221 mm) and the service limit is 0.009 inch (0.221 mm).

    Click image to see an enlarged view

    Fig. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing

  4.  
  5. Replace the oil pump assembly if the clearance exceeds the service limit.
  6.  
  7. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover. The production clearance is 0.003-0.004 inch (0.064-0.109 mm) and the service limit is 0.004 inch (0.109 mm).

    Click image to see an enlarged view

    Fig. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover

  8.  
  9. Replace the oil pump assembly if the clearance exceeds the service limit.
  10.  
  11. Calculate the driven gear shaft to bushing clearance.
    1. Measure the driven gear shaft outside diameter. The production specification is (0.785-0.786 inch (19.947-19.960 mm) and the service limit is 0.782 inch (19.86 mm).
    2.  
    3. Measure the driven gear bushing inside diameter. The production value is 0.787 inch (20 mm).
    4.  
    5. Calculate the driven gear shaft to bushing clearance. The service limit is 0.006 inch (0.14 mm)
    6.  

  12.  
  13. Replace the oil pump assembly if the clearance exceeds the service limit.

    Click image to see an enlarged view

    Fig. Measuring driven gear shaft and bushing

  14.  
  15. Install the oil pump gear cover to the oil pump assembly.
  16.  
  17. Install the oil pump gear cover bolts.
    1. Tighten the oil pump gear cover bolts to 15 ft. lbs (21 Nm).
    2.  

  18.  

8.1L Engine

CAUTION
Wear safety glasses in order to avoid eye damage.



Click image to see an enlarged view

Fig. Exploded view of oil pump-8.1L engine

  1. Clean the oil pump components in cleaning solvent.
  2.  
  3. Dry the components with compressed air.
  4.  
  5. Inspect the gears (427, 428) for the following:

    Scoring
     
    Chipping
     
    Galling
     
    Excessive wear
     

  6.  
  7. Inspect the oil pump housing for the following:

    Damaged bolt hole threads
     
    Worn oil pump driveshaft bore
     
    Scoring or excessive wear within the housing
     
    Worn driven gear shaft
     

  8.  
  9. Inspect for a collapsed pressure relief valve spring.
  10.  
  11. Inspect the pressure relief valve for scoring or wear. The valve should move freely within the bore of the housing.
  12.  

Removal & Installation



4.3L Engine
  1. Remove or disconnect the following:

    Oil pan
     
    Oil pump mounting bolt
     
    Oil pump
     

  2.  

To install:

  1. Inspect the oil pump locator pins for damage, and replace if required.
  2.  
  3. Clean and inspect the oil pump.
  4.  
  5. Position the oil pump onto the locator pins.
  6.  
  7. Install the oil pump bolt and tighten the bolt to 66 ft. lbs. (90 Nm).
  8.  
  9. Install the oil pan.
  10.  

  1. Remove or disconnect the following:

    Oil pan
     
    Oil pump mounting bolt
     
    Oil pump
     

  2.  

To install:

  1. Inspect the oil pump locator pins for damage, and replace if required.
  2.  
  3. Clean and inspect the oil pump.
  4.  
  5. Position the oil pump onto the locator pins.
  6.  
  7. Install the oil pump bolt and tighten the bolt to 66 ft. lbs. (90 Nm).
  8.  
  9. Install the oil pan.
  10.  

  1. Remove or disconnect the following:

    Oil pan
     
    Oil pump mounting bolt
     
    Oil pump
     

  2.  

To install:

  1. Inspect the oil pump locator pins for damage, and replace if required.
  2.  
  3. Clean and inspect the oil pump.
  4.  
  5. Position the oil pump onto the locator pins.
  6.  
  7. Install the oil pump bolt and tighten the bolt to 66 ft. lbs. (90 Nm).
  8.  
  9. Install the oil pan.
  10.  

4.3L, 5.0L, 5.7L And 7.4L Engines
  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:

    Oil pan.
     
    Oil pump attaching bolt, if equipped
     
    Pick-up tube nut/bolt
     
    Pump along with the pick-up tube and shaft, as necessary
     

  4.  
  5. Clean all sealing surfaces
  6.  

To install:

  1. Ensure that the pump pick-up 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 pick-up 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.
    NOTE
    If the pump is not primed, the engine could be damaged before it receives adequate lubrication when the engine is started.

  4.  
  5. Install or connect the following:

    Pump, aligning the pump shaft with the oil pump drive gear as necessary. Torque oil pump/pick-up tube retainer(s) to 65 ft. lbs. (90 Nm) on all 4.3L and all V8 Engines.
     
    Oil pan
     

  6.  
  7. Refill the engine crankcase
  8.  
  9. Disable the ignition system; crank engine for approximately 10 seconds to aid in priming the oil pump and reducing the risk of engine damage.
    NOTE
    If the oil pump does not build up oil pressure almost immediately, remove the pan and check for a loose oil pump-to-pick-up tube attachment. If necessary dismantle the pump and pack the pump cavity with petroleum jelly. Running the engine without measurable oil pressure will cause extensive damage.

  10.  

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

    Oil pan.
     
    Oil pump attaching bolt, if equipped
     
    Pick-up tube nut/bolt
     
    Pump along with the pick-up tube and shaft, as necessary
     

  4.  
  5. Clean all sealing surfaces
  6.  

To install:

  1. Ensure that the pump pick-up 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 pick-up 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.
    NOTE
    If the pump is not primed, the engine could be damaged before it receives adequate lubrication when the engine is started.

  4.  
  5. Install or connect the following:

    Pump, aligning the pump shaft with the oil pump drive gear as necessary. Torque oil pump/pick-up tube retainer(s) to 65 ft. lbs. (90 Nm) on all 4.3L and all V8 Engines.
     
    Oil pan
     

  6.  
  7. Refill the engine crankcase
  8.  
  9. Disable the ignition system; crank engine for approximately 10 seconds to aid in priming the oil pump and reducing the risk of engine damage.
    NOTE
    If the oil pump does not build up oil pressure almost immediately, remove the pan and check for a loose oil pump-to-pick-up tube attachment. If necessary dismantle the pump and pack the pump cavity with petroleum jelly. Running the engine without measurable oil pressure will cause extensive damage.

  10.  

 
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