Repair Pontiac Mid-size 1974-1983 Repair Guide

Engine

Print

REMOVAL & INSTALLATION





Click image to see an enlarged view

Fig. Fig. 1 Exploded view of the engine mounts-250 6-cylinder engine shown



Click image to see an enlarged view

Fig. Fig. 2 LeMans, Grand Prix and Ventura/Phoenix engine mounts

151 Four and 250 Six-Cylinder Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly and its connecting hoses.
  4.  
  5. Scribe the outline of the hood hinges on the underside of the hood for later alignment during assembly. Remove the hood.
  6.  
  7. Drain the cooling system and remove the radiator hoses.
  8.  
  9. Disconnect the engine ground strap from the cylinder head.
  10.  
  11. Remove the fan shroud.
  12.  
  13. Remove the positive battery cable at the starter. Tag and disconnect the primary coil wire at the coil.
  14.  
  15. Disconnect the throttle linkage at the carburetor. Tag and disconnect the automatic transmission kick-down linkage, if equipped.
  16.  
  17. Disconnect the fuel line from the fuel pump. Be careful not to strip the threads on the fitting.
  18.  
  19. Tag and remove the alternator wiring and the heater hoses from the engine.
  20.  
  21. Tag and disconnect the vacuum lines and hoses from the engine. If the car has an automatic transmission, remove the cooler lines from the radiator.
  22.  
  23. If the car is equipped with power steering, remove the power steering pump from the engine with the hoses attached.
  24.  
  25. If the car is equipped with air conditioning, remove the compressor from the engine without disconnecting the compressor lines.
  26.  


CAUTION
Under no circumstances should you disconnect the air-conditioner lines. The air conditioning system is charged with R-12, a gas that when released will freeze any surface it comes in contact with, including your eyes. The R-12 gas also becomes poisonous in the presence of flame. All air conditioning discharging and charging should be handled by a qualified air conditioning mechanic.

  1. Remove the radiator.
  2.  
  3. Jack up the car and safely support it with jackstands.
  4.  
  5. Disconnect the exhaust pipe from the exhaust manifold. Remove the starter from the engine.
  6.  
  7. If the car is equipped with a manual transmission, remove the clutch equalizer bar from the engine block.
  8.  
  9. If the car is equipped with an automatic transmission, remove the torque converter cover. Mark the converter and flywheel with a scribe or colored marker to ensure proper reassembly. Turn the crankshaft pulley to gain access to the three bolts which attach the converter to the flywheel, and remove the bolts.
  10.  
  11. If the car is equipped with a manual transmission, remove the bolts which attach the transmission to the bellhousing. On automatic transmission cars, remove the bolts which attach the transmission and raise the transmission slightly.
  12.  
  13. Remove the motor mount through bolts.
  14.  
  15. Attach a chain hoist or other lifting device to the engine, taking all safety precautions.
  16.  
  17. Remove the engine from the car. If the car is equipped with an automatic transmission, make sure the torque converter stays in the transmission; this can be done by attaching the proper size C-clamp to the transmission housing in such a way that the clamp prevents the converter from slipping out.
  18.  

To install:

  1. Lower the engine carefully into the engine compartment. The engine will have to be hanging from the hoist with the rear of the engine on a downward angle. Raise the transmission slightly, using the floor jack.
  2.  
  3. If equipped with an automatic transmission, start the converter pilot shaft into the crankshaft pilot bearing. If equipped with a manual transmission, start the transmission mainshaft into the clutch disc. Both the engine and transmission have to be on the same angle to accomplish this. This operation will most likely entail a considerable bit of maneuvering of the engine and transmission. If the engine hangs up after the shaft enters on manual transmission cars, slowly turn the crankshaft (with the transmission in gear) until the splines mesh.
  4.  
  5. Make sure the exhaust pipe aligns with the manifold as you lower the engine into the engine compartment. Make sure the engine mounts line up.
  6.  
  7. After the engine is down in the engine compartment on its mounts, install the nuts on the engine mount bolts and tighten the motor mount-to-cylinder blockbolts to 33 ft. lbs.
  8.  
  9. Install the bellhousing-to-transmission attaching bolts on manual transmission cars. On automatic transmission cars, bolt the transmission to the engine block.
  10.  
  11. On automatic transmission-equipped cars, install the torque converter-to-flywheel attaching bolts. Make sure the marks made during removal are lined up, as this is critical to the balance of the entire assembly. Turn the crankshaft pulley with the crank pulley bolt (using a socket wrench) to line up the holes.
  12.  
  13. Install the starter and exhaust pipe.
  14.  
  15. On manual transmission cars, install the clutch equalizer bar. On automatic transmission cars, install the torque converter cover.
  16.  
  17. Install the fuel line, vacuum hoses, wiring, heater hoses, throttle linkage and engine ground strap.
  18.  
  19. Install the radiator and radiator hoses. Install the coolant lines on automatic transmission cars.
  20.  
  21. If the car was equipped with air conditioning, install the compressor. Install the power steering pump, if equipped.
  22.  
  23. Lower the car. Install the hood, lining up the scribe marks. Fill the cooling system and connect the battery cables. Give the engine compartment one final, thorough check to make sure all hoses and wiring are properly connected, and that all assemblies are tightened. Start the car and check throttle and transmission linkage for smooth operation.
  24.  

231 and 252 V6 Engines
  1. Scribe marks around the hood hinges and hinge bracket, so the hood can be installed easily. Remove the hood.
  2.  
  3. Disconnect both battery cables.
  4.  
  5. Drain the coolant into a suitable container; it can be reused if in "fresh" condition.
  6.  
  7. Remove the air cleaner.
  8.  
  9. Disconnect the radiator and heater hoses and position them out of the way.
  10.  
  11. On air-conditioned cars, disconnect the A/C compressor ground wire from the mounting bracket. Remove the electrical connector from the compressor clutch, remove the compressor-to-mounting bracket attaching bolts and position the compressor out of the way.
  12.  


CAUTION
If the compressor refrigerant lines do not have enough slack to position the compressor out of the way without discharging the refrigerant lines, the air conditioning system will have to be removed by a trained air conditioning specialist. Under no circumstances should an untrained person attempt to disconnect the air conditioning refrigerant lines. These lines contain pressurized R-12 refrigerant, which can be extremely dangerous.

  1. Remove the fan blade, pulleys and belts.
  2.  
  3. Remove the fan shroud assembly.
  4.  
  5. Remove the power steering pump-to-mounting bracket bolts and position the pump out of the way.
  6.  
  7. Tag, remove and plug the fuel pump hoses.
  8.  
  9. Tag and disconnect the vacuum lines from the engine to parts not attached to the engine.
  10.  
  11. Disconnect and tag the throttle cable, downshift cable and/or throttle valve cable at the carburetor.
  12.  
  13. Disconnect the transmission oil cooler lines at the transmission. Disconnect the oil and coolant sending unit switch connections at the engine.
  14.  
  15. Disconnect the engine-to-body ground strap at the engine.
  16.  
  17. Jack up and support the front end of the car. Disconnect the starter cables and the cable shield from the engine.
  18.  
  19. Disconnect the exhaust pipes from the exhaust manifolds and support the exhaust system.
  20.  
  21. Remove the flywheel cover pan. Remove the flywheel-to-torque converter bolts. Using a scribe or felt tip marker, matchmark the flywheel-to-torque converter relationship for later assembly.
  22.  
  23. Remove the transmission-to-engine attaching bolts from the transmission bell housing.
  24.  
  25. Remove the cruise control bracket, if so equipped.
  26.  
  27. Remove the motor mount bolts.
  28.  
  29. Lower the car and support the transmission with a floor jack.
  30.  
  31. Check to make sure that all wiring and hoses have been disconnected. Attach a lifting device to the engine and raise the engine just enough so that the engine mount through-bolts can be removed.
  32.  
  33. Raise the engine and transmission alternately until the engine can be disengaged and removed.
  34.  
  35. Installation is the reverse of the removal procedure. It may be necessary to alternately raise and lower the transmission to fit the motor mount through-bolts into position. Tighten the through-bolt nuts to 35 ft. lbs. Tighten the automatic transmission-to-engine bolts to 35 ft. lbs.
  36.  

V8 Engines
  1. Drain the cooling system.
  2.  
  3. Scribe the hinge outline on the underside of the hood. Remove the hood attaching bolts and remove the hood.
  4.  
  5. Disconnect the battery cables.
  6.  
  7. Remove the radiator and heater hoses and remove the air cleaner.
  8.  
  9. Disconnect the transmission oil cooler lines. Remove the fan shroud, fan belts, and pulleys.
  10.  
  11. Disconnect the battery ground cable from the engine. Remove the radiator.
  12.  
  13. Disconnect the exhaust pipe or pipes from the exhaust manifold/s.
  14.  
  15. Disconnect the vacuum line from the power brake unit.
  16.  
  17. Disconnect the accelerator-to-carburetor linkage.
  18.  
  19. Disconnect and label all the engine component wiring that would interfere with the engine removal, such as alternator wires, gauge sending unit wires, primary ignition wires, engine-to-body ground strap, etc.
  20.  
  21. Disconnect and plug the gas line at the fuel pump.
  22.  
  23. Detach the power steering pump and position to the left. Do not disconnect the hoses.
  24.  
  25. Detach the air conditioner compressor at the bracket and position to the right. Do not disconnect the hoses.
  26.  


CAUTION
If the compressor refrigerant lines do not have enough slack to position the compressor out of the way without disconnecting the refrigerant lines, the air conditioning system will have to be removed by a trained air conditioning specialist. Under no conditions should an untrained person attempt to disconnect the air conditioning refrigerant lines. These lines contain pressurized R-12 gas which can be extremely dangerous.

  1. Disconnect the start cable and remove the cable shield.
  2.  
  3. Remove the flywheel cover pan. Remove the flywheel-to-torque converter bolts. Matchmark the flywheel and torque converter for reassembly.
  4.  
  5. Separate the engine from the transmission at the bell housing.
  6.  
  7. Remove the cruise control bracket, if so equipped.
  8.  
  9. Support the transmission with a floor jack.
  10.  
  11. Attach a lifting device to the engine and raise the engine slightly so the engine mount through-bolts can be removed.
  12.  
  13. Check to make sure all of the wiring and hoses have been disconnected. Raise the engine enough to clear the motor mounts.
  14.  
  15. Raise the engine and transmission alternately until the engine can be disengaged and removed.
  16.  
  17. Install by reversing the procedure. When installing an engine, the front mounting pad to frame bolts should be the last mounting bolts to be tightened. Note that there are dowel pins in the block that have matching holes in the bellhousing. These pins must be in almost perfect alignment before the engine will go together with the transmission. Tighten the through-bolt nuts to 35 ft. lbs. Tighten the automatic transmission-to-engine bolts to 35 ft. lbs.
  18.  

 
label.common.footer.alt.autozoneLogo