GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Oil Pan

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REMOVAL & INSTALLATION



See Figures 1 and 2

Inline 6-Cylinder

Pan removal for all engines may be easier if the engine is turned to No. 1 cylinder firing position. This positions the crankshaft in the path of least resistance for pan removal.

  1. Disconnect the battery ground cable.
  2.  
  3. Remove the upper radiator mounting bolts or side mount bolt.
  4.  
  5. Position a drain pan to catch any escaping fluid, then remove the upper and lower hoses for the water pump.
  6.  
  7. Install a piece of heavy cardboard between the fan and the radiator in order to protect the components.
  8.  
  9. Disconnect the fuel suction line from the fuel pump.
  10.  
  11. Raise and support the vehicle safely using jackstands, then drain the oil.
  12.  
  13. Remove the starter assembly.
  14.  
  15. Remove the flywheel lower pan or converter lower pan and splash shield.
  16.  
  17. Rotate the crankshaft until the timing mark on the damper is at the six o'clock position.
  18.  
  19. Remove the brake line retaining bolts from the crossmember and move the brake line out of the way.
  20.  
  21. Remove the through-bolts from the front motor mounts.
  22.  
  23. Remove the oil pan bolts.
  24.  
  25. Slowly raise the engine until the motor mounts can be removed from the frame brackets.
  26.  
  27. Remove the mounts and continue to raise the engine until it has been raised three inches. Make sure that none of the engine mounted components are damaged by contact with the vehicle's body or frame.
  28.  
  29. Remove the oil pan by pulling it down from the engine and then twisting it into the opening left by the removal of the left engine mount.
  30.  
  31. When the pan is clear of the engine, tilt the front up and remove it by pulling it down and to the rear.
  32.  

To install:
  1. Thoroughly clean the gasket mating surfaces.
  2.  
  3. Install the oil pan to the engine block by reversing the tilting necessary to remove it. Be sure to use a new gasket during installation.
  4.  
  5. Install the oil pan retaining bolts, then torque the side bolts to 6-8 ft.lbs. (8-11 Nm) and the end bolts to 9-12 ft. lbs. (12-16 Nm).
  6.  
  7. Install the motor mounts, then carefully lower the engine into position and install the mount through-bolts.
  8.  
  9. Reposition the brake line and install the brake line retaining bolts to the crossmember.
  10.  
  11. Install the flywheel lower pan or converter lower pan and splash shield.
  12.  
  13. Install the starter assembly.
  14.  
  15. Make sure the oil pan drain plug is installed, then remove the jackstands and carefully lower the vehicle.
  16.  
  17. Fill the engine crankcase with the proper amount of clean engine oil. This should be done right away to eliminate the danger of forgetting it later and attempting to start a dry engine.
  18.  
  19. Connect the fuel suction line to the fuel pump.
  20.  
  21. Remove the cardboard from between the fan and the radiator.
  22.  
  23. Connect the upper and lower hoses to the water pump.
  24.  
  25. Install the upper radiator mounting bolts or side mount bolt.
  26.  
  27. Connect the negative battery cable.
  28.  
  29. Check the engine oil level and add, as necessary.
  30.  
  31. Run the engine and check for leaks, then check and top off the coolant, as necessary.
  32.  



Click image to see an enlarged view

Fig. Fig. 1: Loosen and remove the oil pan retaining bolts



Click image to see an enlarged view

Fig. Fig. 2: Tilt and lower the oil pan from the engine

V8 Engines
1964-68
  1. Remove the engine from the chassis.
  2.  
  3. Remove the bellhousing or converter underpan.
  4.  
  5. Remove the starter assembly.
  6.  
  7. Remove the oil pan retaining bolts, then remove the pan from the engine block.
  8.  

To install:
  1. Using a new gasket and/or sealer, as applicable, install the oil pan to the engine block and secure using the retaining bolts.
  2.  
  3. Install the starter assembly.
  4.  
  5. Install the bellhousing or converter underpan.
  6.  
  7. Install the engine to the chassis.
  8.  

1969 WITH 8-396 ,1969 WITH MANUAL TRANSMISSION OR 1970-72 WITH 8-396 AND 8-402
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner, dipstick, distributor cap, radiator shroud and upper mounting panel.
  4.  
  5. On big block models, place a piece of heavy cardboard between the radiator and the fan in order to protect the components.
  6.  
  7. Disconnect the engine ground straps. Remove the fuel pump on 307 and 350 engines.
  8.  
  9. Disconnect the accelerator control cable.
  10.  
  11. Drain the engine oil. Remove the filter on 307 and 350 engines.
  12.  
  13. Remove the driveshaft and plug the rear of transmission.
  14.  
  15. Remove the starter assembly.
  16.  
  17. Disconnect the transmission linkage at the transmission or remove the floorshift lever.
  18.  
  19. Disengage the speedometer cable and the back-up switch connector.
  20.  
  21. On manual transmission vehicles, disconnect the clutch cross-shaft at the frame. On automatic transmission vehicles, disconnect the cooler lines, detent cable, rod or switch wire, and the modulator pipe.
  22.  
  23. Remove the crossmember bolts. Jack up the engine and move the crossmember rearward.
  24.  
  25. Disconnect the dual exhaust pipes or remove the crossover.
  26.  
  27. Remove the flywheel housing cover.
  28.  
  29. Remove the transmission assembly.
  30.  
  31. Remove the flywheel housing and throwout bearing (manual transmission only).
  32.  
  33. Remove the front engine mount through-bolts.
  34.  
  35. Raise the rear of the engine approximately 4 in. and support the engine using a hoist.
  36.  
  37. Raise the front of the engine approximately 4 in. and insert 2 in. blocks under the front engine mounts.
  38.  
  39. Rotate the crankshaft until the timing mark on the torsional damper is at the six o'clock position.
  40.  
  41. Unbolt and remove the oil pan.
  42.  

To install:
  1. Thoroughly clean the gasket mating surfaces.
  2.  
  3. Using a new gasket and/or sealer, as applicable, install the oil pan to the engine block and secure using the retaining bolts.
  4.  
  5. Remove the blocks and lower the engine into position, then install the engine mount through-bolts.
  6.  
  7. Install the flywheel housing and throwout bearing (manual transmission only).
  8.  
  9. Install the transmission assembly.
  10.  
  11. Install the flywheel housing cover.
  12.  
  13. Connect the dual exhaust pipes or install the crossover.
  14.  
  15. Reposition and secure the crossmember using the retaining bolts. If necessary, jack up the engine slightly for the necessary clearance.
  16.  
  17. On manual transmission vehicles, connect the clutch cross-shaft at the frame.
  18.  
  19. On automatic transmission vehicles, connect the cooler lines, detent cable, rod or switch wire, and the modulator pipe.
  20.  
  21. Engage the speedometer cable and the back-up switch connector.
  22.  
  23. Connect the transmission linkage at the transmission or install the floorshift lever.
  24.  
  25. Install the starter assembly.
  26.  
  27. Install the driveshaft and plug the rear of transmission.
  28.  
  29. For 307 and 350 engines, install a new oil filter.
  30.  
  31. Refill the engine crankcase with oil.
  32.  
  33. Connect the accelerator control cable.
  34.  
  35. Connect the engine ground straps.
  36.  
  37. For 307 and 350 engines, install the fuel pump assembly.
  38.  
  39. If applicable, remove the cardboard from between the radiator and the fan.
  40.  
  41. Install the air cleaner, dipstick, distributor cap, radiator shroud and upper mounting panel.
  42.  
  43. Connect the negative battery cable.
  44.  
  45. Run the engine and check for leaks.
  46.  

1969-78
  1. Disconnect the negative battery cable.
  2.  
  3. As a precaution, remove the distributor cap to keep it from breaking from contact with the firewall when the engine is raised.
  4.  
  5. Remove the fan shroud retaining bolts.
  6.  
  7. On earlier models, it may be necessary to remove the radiator upper mounting panel.
  8.  
  9. Raise and support the vehicle safely using jackstands, then drain the engine oil.
  10.  
  11. Disconnect the exhaust pipes or crossover pipes.
  12.  
  13. On automatic transmission equipped vehicles, remove the converter housing underpan and splash shield.
  14.  
  15. Rotate the crankshaft until the timing mark on the torsional dampener is at the six o'clock position.
  16.  
  17. The starter can be swung out of the way by disconnecting the brace at the starter, removing the inboard starter bolt and loosening the outboard starter bolts. On 1970 small block V8 engines, remove the fuel pump.
  18.  
  19. Remove the front engine mount through-bolts.
  20.  
  21. Raise the engine and insert blocks, at least 3 inches thick, under the engine mounts.
  22.  
  23. Remove the oil pan bolts and remove the oil pan.
  24.  

To install:
  1. Thoroughly clean the gasket and seal surfaces .
  2.  

If the crankshaft was rotated while the pan was off, place the timing mark at the six o'clock position.

  1. Install the oil pan to the engine using new gaskets and seals.
  2.  
  3. Remove the blocks and carefully lower the engine, then install the front engine mount through-bolts.
  4.  
  5. Swing the starter back into position and secure.
  6.  
  7. On 1970 small block V8 engines, install the fuel pump.
  8.  
  9. On automatic transmission equipped vehicles, install the converter housing underpan and splash shield.
  10.  
  11. Connect the exhaust pipes or crossover pipes.
  12.  
  13. Make sure the oil pan drain plug is installed, then remove the jackstands and carefully lower the vehicle.
  14.  
  15. Refill the engine crankcase with clean oil right away. This will prevent an accidental attempt to start a dry engine.
  16.  
  17. If removed, install the radiator upper mounting panel.
  18.  
  19. Install the fan shroud retaining bolts.
  20.  
  21. Install the distributor cap.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Run the engine and check for leaks.
  26.  

1979-88
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly, the upper radiator mounting panel and the fan shroud.
  4.  
  5. Raise and support the vehicle safely using jackstands. Drain the oil from the engine.
  6.  
  7. Remove the distributor cap and the fan assembly.
  8.  
  9. If equipped, disconnect the AIR hose from the converter pipe and the AIR pipe from the exhaust manifold.
  10.  
  11. Remove the exhaust crossover pipe from the manifold and the catalytic converter.
  12.  

On some models, it may be necessary to remove the starter.

  1. If equipped with an automatic transmission, remove torque converter housing cover plate and disconnect the transmission oil cooler lines at the oil pan.
  2.  
  3. If equipped with a manual transmission, remove the starter and the flywheel housing cover plate.
  4.  
  5. Rotate crankshaft until timing mark on torsional damper is at 6 o'clock position, this positions the crankshaft throw in the horizontal place.
  6.  
  7. Remove front engine mount through bolts.
  8.  
  9. Carefully raise the engine and insert blocks under engine mounts.
  10.  

The block thickness should be 3 in.

  1. Remove the oil pan bolts and lower the pan from the engine block.
  2.  

To install:
  1. Using a putty knife, clean the gasket mounting surfaces.
  2.  
  3. Install the oil pan using a new gasket and sealant, then torque the oil pan bolts to 7 ft. lbs. (9 Nm).
  4.  
  5. Remove the blocks and carefully lower the engine, then install the engine mount bolts and tighten to 50 ft. lbs. (68 Nm).
  6.  
  7. If equipped with a manual transmission, install the starter and the flywheel housing cover plate.
  8.  
  9. If equipped with an automatic transmission, install the torque converter housing cover plate and connect the transmission oil cooler lines at the oil pan.
  10.  
  11. Install the exhaust crossover pipe to the manifold and the catalytic converter.
  12.  
  13. If removed, install the starter assembly.
  14.  
  15. If equipped, connect the AIR hose to the converter pipe and the AIR pipe to the exhaust manifold.
  16.  
  17. Install the distributor cap and the fan assembly.
  18.  
  19. Make sure the drain plug is installed in the oil pan, then remove the jackstands and carefully lower the vehicle.
  20.  
  21. Refill the engine crankcase with clean oil right away. This will prevent an accidental attempt to start a dry engine.
  22.  
  23. Install the air cleaner assembly, the upper radiator mounting panel and the fan shroud.
  24.  
  25. Connect the negative battery cable.
  26.  
  27. Run the engine and check for leaks.
  28.  

V6 Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the upper half of the radiator fan shroud.
  4.  
  5. Raise the front of the vehicle and support safely using jackstands, then drain the engine oil.
  6.  
  7. Unscrew the exhaust pipe cross-over tube mounting nuts at the manifold. Lower the crossover tube.
  8.  
  9. On models which are equipped with an automatic transmission, remove the torque converter cover, and the oil cooler lines at the oil pan.
  10.  
  11. Remove the upper bolt on the starter brace and then remove the inboard starter bolt ad swing the starter assembly aside.
  12.  
  13. If equipped with Air Injection Reaction (AIR) system, disconnect the AIR hose from the converter pipe and the AIR pipe from the exhaust manifold.
  14.  
  15. Loosen and remove the left hand motor mount through-bolt and then loosen the through-bolt on the right hand mount.
  16.  
  17. Raise the engine and then reinstall the through-bolt in the left hand motor mount. Do not tighten the bolt.
  18.  
  19. Unscrew the attaching bolts and remove the oil pan from under the engine.
  20.  

To install:
  1. Thoroughly clean the gasket and seal surfaces.
  2.  
  3. Install the oil pan to the engine using new gaskets and seals.
  4.  
  5. Remove the left motor mount through bolt, carefully lower the engine into position.
  6.  
  7. Install and tighten the motor mount through-bolts.
  8.  
  9. If equipped with Air Injection Reaction (AIR) system, connect the AIR hose to the converter pipe and the AIR pipe to the exhaust manifold.
  10.  
  11. Swing the starter assembly into position and secure.
  12.  
  13. On models which are equipped with an automatic transmission, install the torque converter cover, and connect the oil cooler lines to the oil pan.
  14.  
  15. Reposition the crossover tube, then secure using the mounting nuts.
  16.  
  17. Make sure the oil pan drain plug is installed, then remove the jackstands and carefully lower the vehicle.
  18.  
  19. Refill the engine crankcase with clean oil. This should be done right away in order to prevent an accidental attempt to start a dry engine.
  20.  
  21. Install the upper half of the radiator fan shroud.
  22.  
  23. Connect the negative battery cable, then run the engine and check for leaks.
  24.  

Diesel Engines

See Figure 3

  1. Disconnect the batteries and remove the dipstick.
  2.  
  3. Remove the vacuum pump and drive (with air conditioning) or the oil pump drive (without air conditioning).
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Diesel oil cooler lines, 263 V6 shown

  1. Remove the upper radiator support and fan shroud.
  2.  
  3. Raise and support the vehicle safely using jackstands, then drain the engine oil from the crankcase.
  4.  
  5. Remove the flywheel cover.
  6.  
  7. Disconnect the exhaust and crossover pipes.
  8.  
  9. Remove the oil cooler lines at the filter base.
  10.  
  11. Remove the starter assembly. Support the engine with a jack.
  12.  
  13. Remove the engine mounts from the block.
  14.  
  15. Raise the front of the engine and remove the oil pan.
  16.  

To install:
  1. Thoroughly clean the gasket and seal surfaces.
  2.  
  3. Install the oil pan to the engine using new gaskets and seals.
  4.  
  5. Lower the front of the engine and secure the engine mounts to the block.
  6.  
  7. Remove the engine support jack, then install the starter assembly.
  8.  
  9. Install the oil cooler lines at the filter base.
  10.  
  11. Connect the exhaust and crossover pipes.
  12.  
  13. Install the flywheel cover.
  14.  
  15. Make sure the oil drain plug is installed, then remove the jackstands and carefully lower the vehicle.
  16.  
  17. Immediately refill the engine crankcase with clean oil. This will prevent an accidental attempt to start a dry engine.
  18.  
  19. Install the upper radiator support and fan shroud.
  20.  
  21. Install the vacuum pump and drive (with air conditioning) or the oil pump drive (without air conditioning).
  22.  
  23. Install the dipstick and connect the batteries.
  24.  
  25. Run the engine and check for leaks.
  26.  

 
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