GM Bonneville/Eighty Eight/LeSabre 1986-1999

Engine

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REMOVAL & INSTALLATION



In the process of removing the engine, you will come across a number of steps which call for the removal of a separate component or system, such as "disconnect the exhaust system" or "remove the radiator." In most instances, a detailed removal procedure can be found elsewhere in this repair guide.

It is virtually impossible to list each individual wire and hose which must be disconnected, simply because so many different model and engine combinations have been manufactured. Careful observation and common sense are the best possible approaches to any repair procedure.

Removal and installation of the engine can be made easier if you follow these basic points:

  1. If you have to drain any of the fluids, use a suitable container.
  2.  
  3. Always tag any wires or hoses and, if possible, the components they came from before disconnecting them.
  4.  
  5. Because there are so many bolts and fasteners involved, store and label the retainers from components separately in muffin pans, jars or coffee cans. This will prevent confusion during installation.
  6.  
  7. After unbolting the transmission or transaxle, always make sure it is properly supported.
  8.  
  9. If it is necessary to disconnect the air conditioning system, have this service performed by a qualified technician using a recovery/recycling station. If the system does not have to be disconnected, unbolt the compressor and set it aside.
  10.  
  11. When unbolting the engine mounts, always make sure the engine is properly supported. When removing the engine, make sure that any lifting devices are properly attached to the engine. It is recommended that if your engine is supplied with lifting hooks, your lifting apparatus be attached to them.
  12.  
  13. Lift the engine from its compartment slowly, checking that no hoses, wires or other components are still connected.
  14.  
  15. After the engine is clear of the compartment, place it on an engine stand or workbench.
  16.  
  17. After the engine has been removed, you can perform a partial or full teardown of the engine using the procedures outlined in this repair guide.
  18.  

3.8L (VIN 3 and C) Engine

See Figures 1 through 9

  1. Properly relieve the fuel system pressure.
  2.  
  3. If not done already, disconnect the negative battery cable.
  4.  
  5. Using a scribing tool, matchmark the hood hinges and remove the hood.
  6.  
  7. Label and disconnect the air flow sensor wiring.
  8.  
  9. Remove the air intake duct. Remove the throttle cable and bracket from the throttle body. Place a clean drain pan under the radiator, open the draincock and drain the cooling system.
  10.  
  11. Raise and safely support the vehicle.
  12.  
  13. Drain the engine oil into a suitable container.
  14.  
  15. Remove the exhaust pipe-to-exhaust manifold bolts and separate the exhaust pipe.
  16.  
  17. Remove the engine mount bolts.
  18.  



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Fig. Fig. 1: Engine-to-transaxle mounting location - 3.8L (VIN C) engine



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Fig. Fig. 2: Engine mounting - 3.8L (VIN C) engine

  1. If equipped with a driveline vibration absorber, remove the bolts and disconnect the absorber.
  2.  
  3. Tag and detach the electrical connectors from the starter. Remove the starter-to-engine bolts and the starter.
  4.  
  5. If equipped with A/C, remove the compressor mounting bolts and position aside. Do not discharge the system or disconnect the refrigerant lines.
  6.  
  7. Place a pan under the power steering gear. Disconnect the hydraulic lines and drain the fluid. Use a length of wire to hold the hoses aside.
  8.  
  9. Remove the lower transaxle-to-engine bolts.
  10.  

One bolt is situated between the transaxle case and the engine block. It is installed in the opposite direction to the other bolts.

  1. Remove the flywheel cover. Matchmark the flexplate-to-torque converter relationship to insure proper alignment upon installation. Remove the flexplate-to-torque converter bolts.
  2.  
  3. Remove the engine support bracket-to-transaxle bolts and the bracket. Lower the vehicle.
  4.  
  5. Attach an engine hoist to the engine lift brackets and support the engine.
  6.  
  7. Remove the radiator and heater hoses from the engine and position them aside.
  8.  
  9. Label and disconnect the hoses from the vacuum modulator and canister purge lines.
  10.  
  11. Tag and detach the engine electrical wiring harness(es) and position them out of way.
  12.  
  13. Remove the upper transaxle-to-engine bolts.
  14.  
  15. Carefully remove the engine from the from the vehicle with the engine hoist. Mount the engine on a suitable workstand.
  16.  



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Fig. Fig. 3: Once the engine is removed, it can be disassembled for rebuilding purposes

To install:
  1. Use the engine hoist to carefully lower the engine into the vehicle.
  2.  



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Fig. Fig. 4: Use a suitable engine hoist to slowly, and carefully, lower the engine into the engine compartment



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Fig. Fig. 5: Carefully guide the engine downward into the engine compartment



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Fig. Fig. 6: Make sure not to pinch any wires, or damage any components when installing the engine

  1. Installation of the engine is the reverse of the removal procedure. Please note the following important steps:
  2.  
  3. Attach all electrical connections and vacuum lines as tagged during removal, making sure the lines are routed properly.
  4.  
  5. There are two studs on the exhaust manifold which must be aligned with the holes in the exhaust pipe while the engine is being lowered into the compartment. They cannot be aligned once the engine is lowered into the vehicle, as the exhaust pipe cannot be moved rearward enough to accomodate the studs.
  6.  



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Fig. Fig. 7: There are two exhaust manifold studs (one is broken on this vehicle) which must be aligned with the exhaust pipe



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Fig. Fig. 8: Location of the exhaust pipe flange holes with which the studs must be aligned



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Fig. Fig. 9: You MUST align the studs with the flange holes, while lowering the engine

  1. Tighten the following components to specifications:
    1. Engine mount bolts: 70 ft. lbs. (95 Nm).
    2.  
    3. Torque converter bolts: 46 ft. lbs. (62 Nm).
    4.  
    5. Lower transaxle-to-engine bolts, tighten: 55 ft. lbs. (75 Nm).
    6.  
    7. Starter mounting bolts: 35 ft. lbs. (47 Nm).
    8.  

  2.  
  3. Install the hood assembly.
  4.  
  5. Connect the negative battery cable. Refill the cooling system and the crankcase.
  6.  
  7. Start the engine, allow it to reach normal operating temperatures and check for leaks. Check the fluid levels, and add as necessary.
  8.  

3.8L (VIN L, K and 1) Engine

See Figures 10 and 11

  1. Properly relieve the fuel system pressure.
  2.  
  3. If not already done, disconnect the negative battery cable.
  4.  
  5. Using a marker or scribing tool, matchmark the hood hinges and remove the hood.
  6.  
  7. Drain the coolant and the engine oil from the vehicle into suitable containers.
  8.  
  9. Remove the strut tower cross brace. Disconnect the windshield washer, radiator and heater supply hoses.
  10.  
  11. Disconnect the wiring from the starter. Disconnect the main wiring at the harness near the relay center.
  12.  
  13. Remove the drive belt(s). Unbolt the power steering pump and position aside.
  14.  
  15. Remove the air inlet duct and the air cleaner assembly. Disconnect the throttle cable from the linkage.
  16.  
  17. Tag and detach the wiring harness connectors from the MAT sensor, throttle position switch, idle air control valve and oxygen sensor.
  18.  
  19. Disconnect the ignition coil ground strap from the fender inner panel.
  20.  
  21. Detach the fuel lines from the fuel rail and from the pressure regulator.
  22.  
  23. Disconnect the emission control hoses from the throttle body connections.
  24.  
  25. Tag and detach the brake booster and heater control hoses from the vacuum connections.
  26.  
  27. Raise and safely support the vehicle.
  28.  
  29. Disconnect the exhaust pipe from the right side manifold and disconnect the vacuum lines from the cruise control and servo assembly.
  30.  
  31. Attach a suitable engine lifting device to the engine and raise, so that it begins to support the engine.
  32.  
  33. If equipped with A/C, unbolt the compressor and tie it back away from the engine. If equipped with an engine oil cooler, disconnect the cooler lines.
  34.  
  35. Remove the front engine mount and remove the right front engine-to-transaxle bracket.
  36.  



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Fig. Fig. 10: Front engine mount assembly - 3.8L (VIN 1 and L) engine



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Fig. Fig. 11: Engine mounting bracket - 3.8L (VIN 1 and L) engine

  1. Use a suitable jack to support the transaxle, then remove the engine to transaxle bolts. Remove the flywheel cover.
  2.  
  3. Remove the torque converter-to-flywheel bolts and use a scribe to matchmark the proper flywheel-to-torque converter relationship.
  4.  
  5. Separate the engine from the transaxle, then remove the engine from the vehicle using a lifting device. Mount the engine on a suitable workstand.
  6.  

To install:
  1. Use the engine hoist to carefully lower the engine into the vehicle.
  2.  
  3. Installation of the engine is the reverse of the removal procedure. Please note the following important steps:
  4.  
  5. Attach all electrical connections and vacuum lines as tagged during removal, making sure the lines are routed properly.
  6.  
  7. Make sure the flywheel and converter are aligned properly before installation.
  8.  
  9. Fill the coolant to the proper level and refill the engine oil.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Start the engine and check for fluid or oil leakage. Check the fluid levels and add as necessary.
  14.  

 
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