GM Firebird 1967-1981 Repair Guide

Oil Pan

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REMOVAL & INSTALLATION OHC 230 and 250 Engines



  1. Disconnect the battery cables.
  2.  
  3. Remove the air cleaner assembly.
  4.  


CAUTION
Please refer to Repair Guide before discharging the compressor or disconnecting air conditioning lines. Damage to the air conditioning system or personal injury could result. Consult your local laws concerning refrigerant discharge and recycling. In many areas it may be illegal for anyone but a certified technician to service the A/C system. Always use an approved recovery station when discharging the air conditioning.

  1. On air conditioned cars, remove the compressor from the mounting brackets and position it to one side.
  2.  
  3. Inspect all water hoses and wiring harness for routing and possible interference. (Engine will be raised at least 2 in.).
  4.  

Before raising the car, prop the hood open at least 6 in. to ensure enough clearance between the timing belt cover and the inner hood panel.


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. Raise the car and drain the crankcase.
  2.  
  3. Remove the starter assembly and flywheel cover.
  4.  
  5. Reroute or disconnect any wiring between the bell housing and floor pan to insure against damage when the bell housing contacts the pan.
  6.  
  7. Loosen the transmission insulator-to-crossmember retaining bolts.
  8.  
  9. Remove the right and left engine insulator-to-frame bracket through-bolts.
  10.  
  11. Rotate the harmonic balancer until the timing mark is at bottom. (This properly positions the crankshaft counterweights).
  12.  
  13. With suitable equipment, raise the engine until the insulators clear the frame brackets.
  14.  
  15. Remove the oil pan bolts.
  16.  
  17. Raise the engine. Apply a rearward force on the engine-transmission assembly until the oil pan clears the flywheel housing. Remove the oil pan.
  18.  
  19. Reverse the removal procedure to install the oil pan.
  20.  

OHV 230 and 250 Engines

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the upper radiator mounting bolts or side mount bolts. Remove the upper and lower hoses from the water pump.
  4.  
  5. Install a piece of heavy cardboard between the fan and the radiator.
  6.  
  7. Disconnect the fuel suction line from the fuel pump.
  8.  


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. Raise the car and drain the oil.
  2.  
  3. Remove the starter.
  4.  
  5. Remove the flywheel lower pan or converter lower pan and splash shield.
  6.  
  7. Rotate the crankshaft until the timing mark on the damper is at the six o'clock position.
  8.  
  9. Remove the brake line retaining bolts from the crossmember and move the brake line out of the way.
  10.  
  11. Remove the through-bolts from the front motor mounts.
  12.  
  13. Remove the oil pan bolts.
  14.  
  15. Slowly raise the engine until the motor mounts can be removed from the frame brackets.
  16.  
  17. Remove the mounts and continue to raise the engine until it has been raised 3 in.
  18.  
  19. Remove the oil pan by pulling it down from the engine and twisting it into the opening left by the removal of the left engine mount.
  20.  
  21. When the pan is clear of the engine, tilt the front up and remove it by pulling it down and to the rear.
  22.  

To install:
  1. Install the oil pan gaskets to the engine block.
  2.  
  3. Install the oil pan and tighten the side bolts to 6-8 ft. lbs. and the end-bolts to 9-12 ft. lbs.
  4.  
  5. Install the motor mounts, then install the remaining components using a reverse procedure of removal.
  6.  

231 Engine

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the upper half of the radiator fan shroud.
  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 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. Raise the front of the car and drain the oil.
  2.  
  3. Unscrew the exhaust pipe crossover tube mounting nuts at the manifold. Lower the crossover tube.
  4.  
  5. On models which are equipped with automatic transmissions, remove the torque converter cover.
  6.  
  7. Remove the upper bolt on the starter brace and remove the inboard starter bolt, then swing the starter assembly aside.
  8.  
  9. Loosen and remove the left-hand motor mount through-bolt and loosen the through-bolt on the right-hand mount.
  10.  
  11. Raise the engine and reinstall the through-bolt in the left-hand motor mount. Do not tighten the bolt.
  12.  
  13. Unscrew the attaching bolts and remove the oil pan from under the engine.
  14.  
  15. To install, clean all gasket and seal surfaces thoroughly, use new gaskets and seals and reverse the removal procedure.
  16.  

1967-69 326, 350 and 400 Engines

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the distributor cap and fan shield.
  4.  
  5. Remove the fan and fan pulley on air conditioned models.
  6.  
  7. Disconnect the engine ground straps.
  8.  


CAUTION
Please refer to Repair Guide before discharging the compressor or disconnecting air conditioning lines. Damage to the air conditioning system or personal injury could result. Consult your local laws concerning refrigerant discharge and recycling. In many areas it may be illegal for anyone but a certified technician to service the A/C system. Always use an approved recovery station when discharging the air conditioning.

  1. On air conditioned models, remove the compressor and swing it out of the way without disconnecting the hoses.
  2.  


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. Jack up the front of car and drain the engine oil.
  2.  
  3. Disconnect the steering idle arm from the frame.
  4.  
  5. Remove the exhaust crossover pipe on single exhaust cars; disconnect the exhaust pipes at the manifold flanges on dual exhaust cars.
  6.  
  7. Remove the starter, starter bracket, and flywheel cover.
  8.  
  9. Support the engine with a chain hoist, then remove the motor mounts and loosen the rear transmission mount.
  10.  

It may be necessary, in some cases, to remove the rear transmission mount.

  1. Remove the oil pan bolts, raise the engine about 4 1 / 2 in., and move the engine forward about 1 1 / 2 in.
  2.  
  3. Remove the oil pan by rotating it clockwise (to clear oil pump) and pulling it down.
  4.  
  5. To install, reverse the removal procedure.
  6.  

1970-81 265, 301, 305, 350, 400, 403 and 455 Engines

  1. Disconnect the negative battery cable.
  2.  
  3. As a precaution, remove the distributor cap to keep it from getting broken 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.  


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. Raise the vehicle on a hoist and drain the engine oil.
  2.  
  3. Disconnect the exhaust pipes or crossover pipes.
  4.  
  5. On automatic transmission equipped vehicles, remove the converter housing underpan and splash shield.
  6.  
  7. Rotate the crankshaft until the timing mark on the torsional dampener is at the six o'clock position.
  8.  
  9. 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 bolt. On 1970 small block V8 engines, remove the fuel pump.
  10.  
  11. Remove the front engine mount through-bolts.
  12.  
  13. Raise the engine and insert blocks, at least 3 in. thick, under the engine mounts.
  14.  
  15. Remove the oil pan bolts and remove the oil pan.
  16.  
  17. To install, clean all gasket and seal surfaces thoroughly, use new gaskets and seals, and reverse the removal procedure.
  18.  

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

 
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