GM Full-Size Trucks 1988-1998 Repair Information

Oil Pan

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REMOVAL & INSTALLATION



4.3L Engines
1988-95 Models

See Figure 1

A one-piece oil pan gasket is used.

  1. Disconnect the negative battery cable. Raise the vehicle, support it safely, and drain the engine oil.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of a typical oil pan-1988-95 4.3L engines

  1. Remove the exhaust crossover pipe.
  2.  
  3. Remove the torque converter cover (on models with automatic transmission).
  4.  
  5. If equipped, remove the strut rod brackets at the front engine mountings.
  6.  
  7. If equipped, remove the Strut rods at the flywheel cover, at the engine mounts and the flywheel cover.
  8.  
  9. Remove the starter motor.
  10.  
  11. Remove the front propeller shaft (K truck only).
  12.  
  13. Remove the underbody protection shield (K truck only).
  14.  
  15. Remove the front drive axle (K truck only).
  16.  
  17. Remove the oil pan bolts, nuts and reinforcements.
  18.  
  19. Remove the oil pan and gaskets.
  20.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize you exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

To install:
  1. Thoroughly clean all gasket surfaces.
  2.  
  3. Apply a suitable sealant such as GM part number 1052080 or its equivalent to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Apply the sealant about 1 inch (25mm) in both directions from each of the four corners.
  4.  
  5. Install the oil pan and new gasket.
  6.  
  7. Install the oil pan bolts, nuts and reinforcements. Tighten the pan bolts to 100 inch lbs. (11 Nm). Tighten the nuts at the corners to 17 ft. lbs. (23 Nm).
  8.  
  9. Install the transmission oil cooler line bracket (on models with automatic transmission).
  10.  
  11. Install the front drive axle (K trucks only).
  12.  
  13. Install the front propeller shaft (K trucks only).
  14.  
  15. Install the underbody protection shields (K trucks only).
  16.  
  17. Install the starter motor.
  18.  
  19. Install the strut rod brackets at the front engine mountings.
  20.  
  21. Install the strut rods at the flywheel cover, if removed.
  22.  
  23. Install the torque converter cover (on models with automatic transmission), if removed.
  24.  
  25. Install the exhaust crossover pipe.
  26.  
  27. Fill the crankcase.
  28.  
  29. Connect the negative battery cable.
  30.  

1996-98 models

See Figure 2

  1. Disconnect the negative battery cable. Raise the vehicle, support it safely, and drain the engine oil.
  2.  
  3. Remove the oil filter.
  4.  
  5. Remove the oil cooler lines from the oil pan and from the adapter.
  6.  
  7. Remove the oil filter adapter.
  8.  
  9. Remove the starter and starter opening shield, If equipped.
  10.  
  11. Disconnect the transmission oil cooler lines (on models with automatic transmission only).
  12.  
  13. Remove the front drive axle tube mount nuts and the lower drive axle bushing bolt.
  14.  
  15. Remove the rubber bellhousing plugs.
  16.  
  17. Remove the oil pan bolts and nuts.
  18.  
  19. Remove the oil pan and gaskets.
  20.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize you exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

To install:
  1. Thoroughly clean all gasket surfaces.
  2.  
  3. Apply a suitable sealant such as GM part number 12346192 or its equivalent to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Apply the sealant about 1 inch (25mm) in both directions from each of the four corners.
  4.  
  5. Install the oil pan and new gasket.
  6.  
  7. Install the oil pan bolts and studs in the sequence illustrated.
  8.  
  9. Install the rubber bellhousing plugs.
  10.  
  11. Use a feeler gauge to check the clearance between the three oil pan-to-transmission contact points. If the clearance exceeds 0.010 inch (0.254mm) at any of the points, adjust the pan until the clearance is within specifications.
  12.  
  13. Once the pan clearance is within specifications, tighten the oil pan retainers in sequence to 18 ft. lbs. (25 Nm).
  14.  
  15. Attach the transmission oil cooler lines (on models with automatic transmission).
  16.  
  17. Install the starter motor opening shield and the starter motor.
  18.  
  19. Install oil filter adapter, oil cooler and the oil filter.
  20.  
  21. Install the front drive axle tube mount nuts.
  22.  
  23. Install the lower drive axle bushing bolt.
  24.  
  25. Fill the crankcase.
  26.  
  27. Connect the negative battery cable.
  28.  



Click image to see an enlarged view

Fig. Fig. 2: Oil pan bolt/stud tightening sequence-1996-98 4.3L models

4.8L Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the truck on jackstands.
  4.  
  5. Drain the engine oil.
  6.  
  7. Remove the flywheel cover.
  8.  
  9. Remove the starter assembly.
  10.  
  11. Remove the engine mount through-bolts from the engine front mounts.
  12.  
  13. Using a floor jack under the damper, raise the engine enough to remove the oil pan.
  14.  
  15. Remove the oil pan retaining bolts. Remove the oil pan from the engine. You may have to break loose the pan with a soft mallet.
  16.  
  17. Thoroughly clean the mating surfaces of the pan and block. If the lips of the pan are bent, straighten them.
  18.  
  19. Installation is the reverse of the removal procedure. Use new gaskets and seals. Tighten the pan-to-front cover bolts to 45 inch lbs. (5 Nm). Tighten the 1 / 4 in. pan-to-block bolts to 80 inch lbs. (9 Nm) and the 5 / 16 in. bolts to 14 ft. lbs. (19 Nm).
  20.  
  21. Fill the engine with the proper grade and viscosity of engine oil and check for leaks.
  22.  

5.0L and 5.7L Engines

2WD MODELS
  1. Disconnect the negative battery cable. Drain the engine oil.
  2.  
  3. Remove the oil dipstick.
  4.  
  5. If necessary remove the exhaust pipe crossover.
  6.  
  7. If equipped with automatic transmission, remove the converter housing pan and the transmission oil cooler line retainer from the bracket.
  8.  
  9. On 1996-98 models, remove the oil filter and if equipped, the oil filter adapter.
  10.  
  11. If necessary, remove the starter brace and bolt and swing the starter aside.
  12.  
  13. Remove the strut rods, if equipped.
  14.  
  15. Remove the oil pan and discard the gaskets.
  16.  

To install:
  1. Apply a suitable sealant such as GM part number 12346192 or its equivalent to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Apply the sealant about 1 inch (25mm) in both directions from each of the four corners.
  2.  
  3. Clean all gasket surfaces and use new gaskets to assemble.
  4.  
  5. Install new gasket and seals.
  6.  
  7. Install the oil pan.
  8.  
  9. On 1988-95 models, tighten the pan bolts to 100 inch lbs. (11 Nm). Tighten the pan nuts to 17 ft. lbs. (23 Nm).
  10.  
  11. On 1996-98 models, tighten the oil pan nuts and bolts to 18 ft. lbs. (25 Nm).
  12.  
  13. Install the strut rods, if equipped.
  14.  
  15. If removed, install starter, starter brace and bolt.
  16.  
  17. If equipped, install the oil filter adapter.
  18.  
  19. If removed, install the oil filter.
  20.  
  21. If equipped with automatic transmission, install the converter housing pan and the transmission oil cooler line retainer to the bracket.
  22.  
  23. Install the exhaust pipe crossover.
  24.  
  25. Install the oil dipstick.
  26.  
  27. Fill the engine with oil and check for leaks.
  28.  

4WD MODELS

See Figures 3, 4, 5, 6, 7, 8, 9, 10 and 11



Click image to see an enlarged view

Fig. Fig. 3: Remove the bolts from the oil filter adapter



Click image to see an enlarged view

Fig. Fig. 4: Remove the oil filter and adapter

  1. Disconnect the negative battery cable. Raise the vehicle, support it safely, and drain the engine oil.
  2.  
  3. On 1996-98 models, remove the engine oil dipstick.
  4.  
  5. Remove the underbody protection shield to access the axle bolts.
  6.  
  7. Remove the transmission oil cooler line bracket from the oil pan, if equipped (on models with automatic transmission only).
  8.  
  9. Remove the front propeller shaft.
  10.  
  11. On 1988-95 models, support the front axle, unfasten the axle mounting bolts and brackets. Rotate the axle to access the oil pan.
  12.  
  13. On 1996-98 models, unfasten the front axle two right side bolts and nuts, one upper bolt and nut. Rotate the drive axle forward and turn the front wheels to the left.
  14.  
  15. On 1988-95 models, remove the strut rods at the flywheel cover.
  16.  
  17. Remove the exhaust pipe crossover.
  18.  
  19. On 1988-95 models, remove the starter.
  20.  
  21. On 1996-98 models, remove the torque converter cover (on models with automatic transmission).
  22.  
  23. Oil cooler lines from the oil pan and from the adapter, if equipped.
  24.  
  25. Oil filter and oil filter adapter, if equipped.
  26.  



Click image to see an enlarged view

Fig. Fig. 5: Remove the strut rod fasteners



Click image to see an enlarged view

Fig. Fig. 6: Remove the strut rods

  1. Remove the oil pan bolts, nuts and reinforcements.
  2.  
  3. Remove the oil pan and gaskets.
  4.  


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize you exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.



Click image to see an enlarged view

Fig. Fig. 7: Remove the torque converter cover



Click image to see an enlarged view

Fig. Fig. 8: Remove the oil pan bolts and nuts

To install:
  1. Thoroughly clean all gasket surfaces and install a new gasket.
  2.  
  3. Apply a suitable sealant such as GM part number 12346192 or its equivalent to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Apply the sealant about 1 inch (25mm) in both directions from each of the four corners.
  4.  
  5. Install the oil pan and new gaskets.
  6.  
  7. Install the oil pan bolts, nuts and reinforcements.
  8.  
  9. On 1988-95 models, tighten the pan bolts to 100 inch lbs. (11 Nm). Tighten the nuts at the corners to 17 ft. lbs. (23 Nm).
  10.  
  11. On 1996-98 models, tighten the oil pan nuts and bolts to 18 ft. lbs. (25 Nm).
  12.  
  13. Install the transmission oil cooler line bracket (on models with automatic transmission).
  14.  
  15. Install oil filter adapter, oil cooler and the oil filter.
  16.  
  17. Install the flywheel/torque converter cover.
  18.  
  19. Install the underbody protection shields.
  20.  
  21. If removed, install the starter.
  22.  
  23. Install the exhaust crossover pipe.
  24.  
  25. Install the strut rods at the flywheel cover, if removed.
  26.  
  27. Install the front drive axle.
  28.  
  29. Install the front propeller shaft.
  30.  
  31. Install the underbody shields.
  32.  
  33. Connect the negative battery cable.
  34.  
  35. Fill the crankcase.
  36.  



Click image to see an enlarged view

Fig. Fig. 9: Remove the oil pan reinforcements



Click image to see an enlarged view

Fig. Fig. 10: Remove the oil pan from the vehicle



Click image to see an enlarged view

Fig. Fig. 11: Remove the old gasket from both mating surfaces

7.4L Engines
1988-95 MODELS

See Figure 12

  1. Disconnect the battery.
  2.  
  3. Remove the fan shroud.
  4.  
  5. Remove the air cleaner.
  6.  
  7. Remove the distributor cap.
  8.  



Click image to see an enlarged view

Fig. Fig. 12: Oil pan-1988-95 7.4L engines

  1. Raise and support the front end on jackstands.
  2.  
  3. Drain the engine oil.
  4.  
  5. Remove the converter housing pan. On 4WD vehicles with automatic transmission, remove the strut rods at the engine mounts.
  6.  
  7. Remove the oil filter.
  8.  
  9. Remove the oil pressure line.
  10.  
  11. Support the engine with a floor jack.
  12.  


WARNING
Do not place the jack under the pan, sheet metal or pulley!

  1. Remove the engine mount through-bolts.
  2.  
  3. Raise the engine just enough to remove the pan.
  4.  
  5. Remove the oil pan and discard the gaskets.
  6.  

To install:
  1. Clean all mating surfaces thoroughly.
  2.  
  3. Apply RTV gasket material to the front and rear corners of the gaskets.
  4.  
  5. Coat the gaskets with adhesive sealer and position them on the block.
  6.  
  7. Install the rear pan seal in the pan with the seal ends mating with the gaskets.
  8.  
  9. Install the front seal on the bottom of the front cover, pressing the locating tabs into the holes in the cover.
  10.  
  11. Install the oil pan.
  12.  
  13. Install the pan bolts, clips and reinforcements. Tighten the pan-to-cover bolts to 70 inch lbs. (8 Nm); the pan-to-block bolts to 13 ft. lbs. (18 Nm).
  14.  
  15. Lower the engine onto the mounts.
  16.  
  17. Install the engine mount through-bolts.
  18.  
  19. Install the oil pressure line.
  20.  
  21. Install the oil filter.
  22.  
  23. Install the converter housing pan.
  24.  
  25. Install the distributor cap.
  26.  
  27. Install the air cleaner.
  28.  
  29. Install the fan shroud.
  30.  
  31. Connect the battery.
  32.  
  33. Fill the crankcase.
  34.  

1996-98 MODELS
  1. Disconnect the negative battery cable and remove the oil level indicator and tube.
  2.  
  3. Raise the vehicle, support it safely with jackstands and drain the oil.
  4.  
  5. Remove the front propeller shaft (K truck only).
  6.  
  7. Remove the underbody protection shield (K truck only).
  8.  
  9. Unfasten the front axle two right side bolts and nuts, one upper bolt and nut. Rotate the drive axle forward and turn the front wheels to the left.
  10.  
  11. Remove the front drive axle (K truck only).
  12.  
  13. Remove the flywheel/torque converter cover.
  14.  
  15. Remove the exhaust crossover pipe.
  16.  
  17. Remove the oil filter and adapter, if equipped.
  18.  
  19. Remove the oil cooler line retainer from the bracket, if equipped.
  20.  
  21. Remove the transmission oil cooler line retainer from the bracket, if equipped.
  22.  
  23. Remove the oil pan bolts, nuts and strut rods, if equipped.
  24.  
  25. Remove the oil pan and gasket.
  26.  

To install:
  1. Thoroughly clean all gasket surfaces and install a new gasket.
  2.  
  3. Apply a suitable sealant such as GM part number 12345739 or its equivalent to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Apply the sealant about 1 inch (25mm) in both directions from each of the four corners.
  4.  
  5. Install the oil pan and new gaskets.
  6.  
  7. Install the oil pan bolts, nuts and strut rods. Tighten the pan bolts and nuts to 18 ft. lbs. (25 Nm).
  8.  
  9. Install the transmission oil cooler line bracket (on models with automatic transmission).
  10.  
  11. Install oil filter adapter, oil cooler and the oil filter.
  12.  
  13. Install the front drive axle (K trucks only).
  14.  
  15. Install the front propeller shaft (K trucks only).
  16.  
  17. Install the underbody protection shields (K trucks only).
  18.  
  19. Install the starter and opening shield.
  20.  
  21. Install the strut rod brackets at the front engine mountings, if removed.
  22.  
  23. Install the strut rods at the flywheel cover, if removed.
  24.  
  25. Install the torque converter cover (on models with automatic transmission), if removed.
  26.  
  27. Install the exhaust crossover pipe, if removed.
  28.  
  29. Connect the negative battery cable.
  30.  
  31. Fill the crankcase.
  32.  

6.2L and 6.5L Diesel Engines
1988-95 MODELS

See Figure 13

  1. If necessary, remove the vacuum pump and drive (with air conditioning or the oil pump drive (without air conditioning).
  2.  
  3. Disconnect the batteries and remove the engine oil dipstick.
  4.  
  5. If necessary, remove the upper radiator support and fan shroud.
  6.  
  7. Raise and support the truck. Drain the oil.
  8.  
  9. Remove the flywheel cover. On 4WD vehicles with automatic transmission, remove the strut rods at the engine mounts.
  10.  
  11. Disconnect the exhaust and crossover pipes, if necessary.
  12.  
  13. If necessary, remove the oil cooler lines at the filter base.
  14.  
  15. If necessary, remove the starter assembly and support the engine with a jack.
  16.  



Click image to see an enlarged view

Fig. Fig. 13: Oil pan-diesel engines

  1. Remove the engine mount through-bolts.
  2.  
  3. Raise the front of the engine and remove the oil pan.
  4.  

To install:
  1. Applt a 3 / 16 inch (5mm) bead of RTV sealant to the oil pan sealing surface, inboard of the bolt holes. The sealer must be wet to the touch when the oil pan is installed.
  2.  
  3. Install the oil pan rear seal, if equipped.
  4.  
  5. Position the oil pan on the block and install the bolts. Tighten the bolts to 89 inch lbs. (10 Nm), except for the two rear bolts. Tighten them to 17 ft. lbs. (23 Nm).
  6.  
  7. Install the engine mount through-bolt.
  8.  
  9. Remove the jack.
  10.  
  11. If removed, install the starter assembly.
  12.  
  13. If removed, install the oil cooler lines at the filter base.
  14.  
  15. Connect the exhaust and crossover pipes.
  16.  
  17. Install the flywheel cover.
  18.  
  19. IF removed, install the upper radiator support and fan shroud.
  20.  
  21. Connect the batteries.
  22.  
  23. Install the engine oil dipstick.
  24.  
  25. If removed, install the vacuum pump and drive (with air conditioning or the oil pump drive (without air conditioning).
  26.  
  27. Fill the crankcase.
  28.  

1996-98 MODELS
  1. Disconnect the batteries and remove the engine oil dipstick.
  2.  
  3. Raise the vehicle, support it with jackstands and drain the engine oil.
  4.  
  5. Remove the oil level tube.
  6.  
  7. Remove the flywheel cover.
  8.  
  9. Remove the oil cooler line clip.
  10.  
  11. If equipped, remove the propeller shaft.
  12.  
  13. Roll the front axle, if equipped.
  14.  
  15. Remove the oil pan bolts, pan and gasket.
  16.  

To install:
  1. Appaly a 1 / 16 inch (2mm) bead of RTV sealant to the oil pan rear seal at the inside corners where the seal meets the rear main bearing cap on the block.
  2.  
  3. Install the oil pan rear seal before the sealer is dry.
  4.  
  5. Install the oil pan rear seal.
  6.  
  7. Position the oil pan on the block and install the bolts. Tighten the bolts to 89 inch lbs. (10 Nm), except for the two rear bolts. Tighten them to 17 ft. lbs. (23 Nm).
  8.  
  9. Install the oil cooler line clip.
  10.  
  11. Install the oil level tube.
  12.  
  13. Install the flywheel cover.
  14.  
  15. If necessary, reposition the front axle.
  16.  
  17. If equipped, install the propeller.
  18.  
  19. Lower the vehicle.
  20.  
  21. Connect the batteries.
  22.  
  23. Install the dipstick.
  24.  
  25. Fill the crankcase.
  26.  

 
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