GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Oil Pan

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Pan removal is possible with the engine in the vehicle on some of the powertrain combinations covered by this guide. If it is possible, it will often require the removal or repositioning of components including, the steering linkage assembly, the forward drive axle and crossmember (4WD) and/or the engine mounts. It is a difficult and tedious task to remove the oil pan with the engine in the vehicle. The chances of contaminating the bearing surfaces or damaging other internal engine components is great. Also, working under the vehicle with the engine jacked up in the frame puts you at great risk for great personal injury. Therefore, it is desirable in most cases to remove the engine in order to gain access to the oil pan.

REMOVAL & INSTALLATION



2.2L Engine

See Figure 1

  1. Remove the engine assembly from the vehicle.
  2.  
  3. If equipped, remove the clutch pressure plate and disc from the engine.
  4.  
  5. Remove the flywheel.
  6.  
  7. Remove the oil pan nuts and bolts, then remove the pan from the bottom of the block.
  8.  

To install:
  1. Carefully clean the gasket mating surfaces of any remaining old gasket or sealer material.
  2.  
  3. Position a new gasket and seal onto the oil pan. Use a thin bead of sealant at either side of the sealer (as shown in the illustration).Use a thin bead of sealant to the oil pan side flanges and the pan surface that contacts the engine front cover.
  4.  
  5. Install the oil pan and tighten the retaining bolts to 89 inch. lbs. (10 Nm).
  6.  
  7. Install the flywheel.
  8.  
  9. If equipped, install the pressure plate and disc.
  10.  
  11. Install the engine to the vehicle.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Oil pan and gasket installation-2.2L engine

2 Wheel Drive 4.3L Engines

See Figure 2

  1. Remove the engine from the vehicle.
  2.  
  3. Remove the oil pan retainers (nuts, studs and/or bolts) and rail reinforcements, if equipped.
  4.  
  5. Remove the rubber bell housing plugs, if equipped.
  6.  
  7. Remove the oil pan from the block.
  8.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces. Make sure that all sealing surfaces are clean and free of oil.
  2.  
  3. Apply 1052080 or an equivalent sealant to the oil pan rail where it contacts the timing cover-to-block joint (front) and the crankshaft rear seal retainer-to-block joint (rear). Continue the bead of sealant about 1 in. (25mm) in both directions from each of the four corners.
  4.  
  5. Using a new gasket, install the oil pan, reinforcements (if equipped) and retainers.
  6.  

On 1996-99 models the alignment between the rear of the pan and rear of the block is critical. The two surfaces must be flush to allow for proper alignment with the transmission housing.

  1. On 1996-99 models, use a feeler gauge to check the clearance between the oil pan-to-transmission contacts. If clearance exceeds 0.011 inch (0.3mm) at any of the three contact points, readjust the pan until the clearance is within specification.
  2.  
  3. Once the pan is in its correct position tighten the retainers to specification:
  4.  

On 1994-95 models.



Bolts: 100 inch lbs. (11 Nm).
 
Nuts at corners: 17 ft. lbs. (23 Nm)
 

On 1996-99 models.



Bolts and studs in the sequence illustrated: 18 ft. lbs. (25 Nm)
 

  1. Install the engine into the vehicle. Refill the crankcase with fresh oil. Start the engine, establish normal operating temperatures and check for leaks.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Oil pan bolt tightening sequence-1996-99 4.3L engine

199497 4 Wheel Drive Models

See Figures 2, 3, 4 and 5



Click image to see an enlarged view

Fig. Fig. 3: Drain the engine oil from the crankcase



Click image to see an enlarged view

Fig. Fig. 4: After unfastening the oil pan bolts remove the oil pan



Click image to see an enlarged view

Fig. Fig. 5: Remove and discard the old oil pan gasket

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the dipstick tube.
  4.  
  5. Raise and support the front of the vehicle safely using jackstands.
  6.  
  7. Remove the drive belt splash shield, the front axle shield, and the transfer case shield.
  8.  
  9. Remove the front skid plate and drain the engine crankcase oil, then remove the flywheel cover.
  10.  
  11. If applicable, disengage the wiring harness bracket at the right side of the oil pan.
  12.  
  13. Remove the left and right motor mount through-bolts.
  14.  
  15. Raise the engine using a suitable lifting device and block in position. This may be accomplished using large wooden blocks between the motor mounts and brackets.
  16.  

Use extreme caution when blocking the engine in position. Get out from underneath the truck and rock the engine slightly once the blocks are in place to be sure the engine is properly supported.

  1. Disconnect the oil cooler line, then remove the oil filter adapter.
  2.  
  3. Remove the pitman arm bolt, then disconnect the pitman arm.
  4.  
  5. Remove the idler arm bolts, then disconnect the idler arm.
  6.  
  7. Remove the front differential through-bolts, then disconnect or remove the front driveshaft (as necessary).
  8.  
  9. Roll the differential assembly forward for clearance.
  10.  
  11. Remove the starter motor retaining bolts, then lower the starter and either remove it from the vehicle or suspend it out of the way using mechanic's wire.
  12.  
  13. Remove the oil pan bolts, nuts and reinforcements, then lower the oil pan and gasket from the vehicle.
  14.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces. Make sure that all sealing surfaces are clean and free of oil.
  2.  
  3. Apply 1052080, or an equivalent sealant to the oil pan rail where it contacts the timing cover-to-block joint (front) and the crankshaft rear seal retainer-to-block joint (rear). Continue the bead of sealant about 1 in. (25mm) in both directions from each of the four corners.
  4.  
  5. Using a new gasket, install the oil pan, reinforcements and retainers. Tighten the bolts to 100 inch lbs. (11 Nm) and the nuts at the corners to 17 ft. lbs. (23 Nm) on 1994-95 models and 18 ft. lbs. (25 Nm) on 1996-97 models in the sequence illustrated.
  6.  


CAUTION
Use a feeler gauge to check the clearance between the three oil pan-to-transmission bell housing contact points. if the clearance exceeds 0.011 in. (0.3mm) at any of the points, move the pan until the clearance is within specifications.

  1. Install the starter motor and secure using the mounting bolts.
  2.  
  3. Roll the differential back into position, then install/connect the front driveshaft. Install the front differential through-bolts.
  4.  
  5. Connect the idler arm and secure using the retaining bolts, then connect the pitman arm and secure using the bolts.
  6.  
  7. Install the transfer case shield.
  8.  
  9. Install the flywheel cover, then install the front skid plate.
  10.  
  11. Install the front axle shield, then install the drive belt splash shield.
  12.  
  13. If applicable, engage the wiring harness bracket at the right side of the oil pan.
  14.  
  15. Remove the jackstands and carefully lower the truck.
  16.  
  17. Install the dipstick, then properly refill the engine crankcase.
  18.  
  19. Connect the negative battery cable.
  20.  
  21. Start the engine, establish normal operating temperatures and check for leaks.
  22.  

199899 4 Wheel Drive Models

See Figure 2

  1. Remove the battery and battery tray.
  2.  
  3. Disconnect the shift cable at the actuator.
  4.  
  5. Raise the vehicle and support it with safety stands.
  6.  
  7. Remove the splash shields from the steering linkage and the oil pan.
  8.  
  9. Drain the engine oil and remove the starter motor.
  10.  
  11. Remove the oil cooler pipes.
  12.  
  13. Remove the front wheels.
  14.  
  15. Unplug the electrical connector at the shift cable housing.
  16.  
  17. Remove the wiring harness bracket from the shift cable housing.
  18.  
  19. Unfasten the shift cable housing bolts and disconnect the shift cable from the differential carrier.
  20.  
  21. Remove both drive axles and the differential.
  22.  
  23. Unfasten the oil pan retainers, then lower the oil pan and gasket from the vehicle.
  24.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces. Make sure that all sealing surfaces are clean and free of oil.
  2.  
  3. Apply 12346141, or an equivalent sealant to the oil pan rail where it contacts the timing cover-to-block joint (front) and the crankshaft rear seal retainer-to-block joint (rear). Continue the bead of sealant about 1 in. (25mm) in both directions from each of the four corners.
  4.  
  5. Using a new gasket, install the oil pan and retainers. Tighten the bolts to 18 ft. lbs. (25 Nm) in the sequence illustrated.
  6.  


CAUTION
Use a feeler gauge to check the clearance between the three oil pan-to-transmission bell housing contact points. if the clearance exceeds 0.011 in. (0.3mm) at any of the points, move the pan until the clearance is within specifications.

  1. Install the differential and the drive axles.
  2.  
  3. Attach the shift cable to the differential carrier and install the shift cable housing bolts.
  4.  
  5. Install the wiring harness bracket at the shift cable housing.
  6.  
  7. Attach the electrical connector at the shift cable housing.
  8.  
  9. Install the front wheels and the oil cooler lines.
  10.  
  11. Install the starter motor and secure using the mounting bolts.
  12.  
  13. Install the splash shields and lower the vehicle.
  14.  
  15. Attach the shift cable at the actuator.
  16.  
  17. Install the battery and battery tray.
  18.  
  19. Properly refill the engine crankcase.
  20.  
  21. Start the engine, establish normal operating temperatures and check for leaks.
  22.  

 
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