GM Astro/Safari 1985-1996 Repair Guide

Oil Pan

Print

REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5, 6 and 7



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of a typical oil pan assembly-early-model 4.3L engine shown



Click image to see an enlarged view

Fig. Fig. 2: RTV sealant application for the 2.5L engine oil pan



Click image to see an enlarged view

Fig. Fig. 3: On most vehicles covered by this guide you will have to unbolt the exhaust pipe for clearance



Click image to see an enlarged view

Fig. Fig. 4: Loosen and remove the oil pan retaining bolts (a variety of ratchet extensions will be helpful)



Click image to see an enlarged view

Fig. Fig. 5: If equipped, remove the oil pan reinforcements ...



Click image to see an enlarged view

Fig. Fig. 6: ... then lower the pan from the engine



Click image to see an enlarged view

Fig. Fig. 7: CAREFULLY remove the old gasket (on 4.3L engines it can be reused if it is not damaged)

1985-90 Models
  1. Disconnect the negative battery cable for safety.
  2.  
  3. Raise and support the front of the vehicle safely using jackstands.
  4.  
  5. Position a catch pan under the crankcase and drain the oil from the engine.
  6.  


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 your 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.

  1. Disconnect the strut rods at the flywheel/torque converter cover, then remove the cover from the bellhousing.
  2.  
  3. Disengage the electrical connectors from the starter, then remove the starter-to-engine bolts, the brace and the starter from the vehicle.
  4.  
  5. Disconnect the exhaust pipe(s) from the exhaust manifold(s) and, if necessary, at the exhaust pipe-to-catalytic converter hanger(s).
  6.  
  7. If necessary, remove the engine mount through-bolts, then using an engine lifting device, raise the engine (as needed) in order to make room for the oil pan removal.
  8.  


WARNING
If it is necessary to raise the engine, do so slowly, continually checking for possible interference with the firewall. DO NOT allow upper engine components to become damaged.

  1. Remove the oil pan-to-engine bolts and nuts (as applicable), then remove the oil pan from the engine.
  2.  
  3. Using a plastic scraper, clean the gasket mounting surfaces. Using solvent, clean the excess oil from the mounting surfaces.
  4.  

To install:
  1. On the 2.5L engine, apply a 1 / 6 in. (4.2mm) bead of RTV sealant to the oil pan flange (keep the bead inside the bolt holes), the rear main bearing, the timing gear cover and the engine block sealing surface. On the 4.3L engine, apply a small amount of RTV sealant to the front and rear corners of the oil pan; too much sealant may prevent sealing of the gasket.
  2.  

The 4.3L engine uses a one piece oil pan gasket.

  1. Use a new gasket (4.3L), RTV sealant and install the oil pan.
  2.  
  3. Tighten the oil pan-to-engine bolts to 100 inch lbs. (11 Nm) and the oil pan-to-engine nuts to 14 ft. lbs. (20 Nm) for the 4.3L.
  4.  
  5. If raised, lower the engine into position and install the mount through-bolts.
  6.  
  7. Reposition and secure the pipe(s) to the exhaust manifold(s).
  8.  
  9. Install the starter motor assembly.
  10.  
  11. Install the flywheel/torque converter cover, then secure the strut rods.
  12.  
  13. Remove the jackstands and carefully lower the vehicle.
  14.  
  15. Immediately refill the crankcase with fresh oil. Don't risk someone accidentally trying to start a dry motor.
  16.  
  17. Connect the negative battery cable, then start the engine, establish normal operating temperatures and check for leaks.
  18.  

1991-95 Models
  1. Disconnect the negative battery cable for safety.
  2.  
  3. Raise and support the front of the vehicle safely using jackstands.
  4.  
  5. Position a catch pan under the crankcase and drain the oil from the engine.
  6.  


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 your 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.

  1. Disconnect the exhaust pipe from the manifolds.
  2.  
  3. Remove the torque converter cover from the bellhousing.
  4.  
  5. Remove the starter assembly from the vehicle.
  6.  
  7. Remove the oil pan-to-engine bolts, nuts and reinforcements, then carefully lower the oil pan from the engine.
  8.  

Remember that no matter how well you drained the crankcase, the oil pan will still be holding a decent amount of slimy residue.

  1. Carefully remove the rubber composite gasket from the mating surface. Take care because if the gasket is free of damage it can be reused.
  2.  
  3. Clean the gasket mounting surfaces of sealant, dirt or other residue. Using solvent, clean the excess oil from the mounting surfaces.
  4.  

To install:
  1. Inspect the oil pan gasket for damage and replace, if necessary. Position the gasket on the oil pan.
  2.  
  3. Apply sealant such as GM 12346141, or equivalent, to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Continue the sealant about 1 in. (25mm) in both directions from the 4 corners.
  4.  
  5. Carefully raise the oil pan into position with the reinforcements and thread the retainers.
  6.  
  7. Tighten the oil pan-to-engine bolts to 100 inch lbs. (11 Nm) and the oil pan-to-engine nuts to 17 ft. lbs. (23 Nm).
  8.  
  9. Install the starter motor assembly.
  10.  
  11. Install the torque converter cover.
  12.  
  13. Reposition and secure the pipe to the exhaust manifolds.
  14.  
  15. Remove the jackstands and carefully lower the vehicle.
  16.  
  17. Immediately refill the crankcase with fresh oil. Don't risk someone accidentally trying to start a dry motor.
  18.  
  19. Connect the negative battery cable, then start the engine, establish normal operating temperatures and check for leaks.
  20.  

1996 Models

See Figures 8, 9, 10, 11 and 12



Click image to see an enlarged view

Fig. Fig. 8: Exploded view of the oil pan mounting-1996 4.3L engines



Click image to see an enlarged view

Fig. Fig. 9: Sealant should be applied to this area during installation-1996 4.3L engines



Click image to see an enlarged view

Fig. Fig. 10: Oil pan retainer torque sequence-1996 4.3L engines



Click image to see an enlarged view

Fig. Fig. 11: Check the oil pan tolerance (pan-to-transmission clearance) as these 3 points



Click image to see an enlarged view

Fig. Fig. 12: Exploded view of the oil filter adapter mounting

Any time the transmission and oil pan are off the engine at the same time, the transmission MUST be installed before the oil pan. This will allow for proper measurement of the oil pan tolerance.

  1. Disconnect the negative battery cable for safety.
  2.  
  3. Raise and support the front of the vehicle safely using jackstands.
  4.  
  5. Position a catch pan under the crankcase and drain the oil from the engine.
  6.  


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 your 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.

  1. Remove the oil filter.
  2.  
  3. Disconnect the oil cooler lines from the oil pan and from the adapter. Immediately plug all openings to prevent system contamination or excessive fluid loss.
  4.  
  5. Remove the oil filter adapter.
  6.  
  7. Remove the starter assembly from the vehicle.
  8.  
  9. Remove the starter shield.
  10.  
  11. If necessary, remove the transmission oil cooler lines. Immediately plug all openings to prevent system contamination or excessive fluid loss.
  12.  
  13. On All Wheel Drive (AWD) vehicles, remove the front drive axle tube mount nuts and the left lower drive axle bushing bolt.
  14.  
  15. Remove the rubber bellhousing plugs.
  16.  
  17. Remove the oil pan-to-engine bolts and studs, then carefully lower the oil pan from the engine.
  18.  

Remember that no matter how well you drained the crankcase, the oil pan will still be holding a decent amount of slimy residue.

  1. Carefully remove the rubber composite gasket from the mating surface. Take care because if the gasket is free of damage it can be reused.
  2.  
  3. Clean the gasket mounting surfaces of sealant, dirt or other residue. Using solvent, clean the excess oil from the mounting surfaces.
  4.  

To install:
  1. Inspect the oil pan gasket for damage and replace, if necessary. Position the gasket on the oil pan.
  2.  
  3. Apply sealant such as GM 12346141, or equivalent, to the front cover-to-block joint and to the rear crankshaft seal-to-block joint. Continue the sealant about 1 in. (25mm) in both directions from the 4 corners.
  4.  
  5. Carefully raise the oil pan into position and thread the retainers finger-tight.
  6.  
  7. Tighten the oil pan-to-engine retainers using the proper torque sequence to 18 ft. lbs. (25 Nm).
  8.  
  9. Use a feeler gauge to check for proper oil pan-to-transmission clearance at the points shown in the accompanying figure. If the clearance exceeds 0.010 in. (0.254) at ANY of the 3 contact points, loosen the retainers and reposition the pan until clearance is correct.
  10.  
  11. If removed, install the transmission oil cooler lines.
  12.  
  13. Install the starter shield.
  14.  
  15. Install the starter motor assembly.
  16.  
  17. Install the oil filter adapter.
  18.  
  19. Remove the plugs, then connect the oil cooler lines. Secure the lines to the oil pan.
  20.  
  21. Install a new oil filter.
  22.  
  23. On AWD vehicles, install the front drive axle tube mount nuts and the left lower drive axle bushing bolt.
  24.  
  25. Remove the jackstands and carefully lower the vehicle.
  26.  
  27. Immediately refill the crankcase with fresh oil. Don't risk someone accidentally trying to start a dry motor.
  28.  
  29. Connect the negative battery cable, then start the engine, establish normal operating temperatures and check for leaks.
  30.  

 
label.common.footer.alt.autozoneLogo