GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 LeSabre 🢒 Engine 🢒 Engine Mechanical - 3.8L 🢒 Engine Replacement

Removal Procedure
  1. Remove the hood. Refer to Hood Replacement in Body Front End.

    2. Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  2. Disconnect the negative battery cable.
  3. Depressurize the fuel lines.
  4. Drain the coolant. Refer to Cooling System Draining and Filling in Engine.
  5. Drain the engine oil.
  6. Remove the radiator hoses.
  7. Remove the heater supply hoses. Refer to Radiator Inlet Hose Replacement in Engine Cooling.
  8. Disconnect the negative battery cable from the engine block.
  9. Remove the engine harness connector at the bulkhead.
  10. Remove the drive belt. Refer to Drive Belt Replacement (VIN K)
  11. For supercharged engines, remove the supercharger belt.
  12. Remove the power steering pump. Set the pump aside. Refer to Power Steering Pump Replacement in Power Steering Systems.
  13. Remove the air flow duct.
  14. Remove the throttle cable from the throttle linkage.
  15. Remove the mounting bracket.
  16. Disconnect the other applicable cables from the engine.
  17. Remove the wiring harness connectors from the following locations:
    18. • The MAT sensor
    • The throttle position sensor
    • The idle air control valve
    • The oxygen sensor
    • The A/C compressor. Refer toCompressor Replacement in Heating, Ventilation and Air Conditioning.
    • The oil pressure switch
    • The power steering cutout switch.
    • The vehicle speed sensor (VSS)
    • The low oil level sensor
  18. Remove the ignition coil assembly ground strap from the fender inner panel attaching screws.
  19. Remove the fuel feed and return lines from the fuel rail and the pressure regulator.
  20. Remove the emission control canister hoses from the throttle body connections.
  21. Remove the brake booster from the engine vacuum connections.
  22. Remove the heater control hoses from the engine vacuum connections.
  23. Raise the vehicle. Support the vehicle suitably. Refer to Lifting and Jacking the Vehicle in General Information.
  24. Remove the exhaust pipe from the right manifold.
  25. Remove the A/C compressor from the engine. Tie the compressor back away from the engine. Refer to Compressor Replacement in Heating, Ventilation and Air Conditioning.
  26. Remove the engine to the transaxle bracket.
  27. Remove the flywheel cover.
  28. Remove the starter motor. Refer to Starter Motor Replacement in Engine Electrical.

    29. Important: Use a scribe in order to mark the relationship between the flywheel and the torque converter. This ensures proper reassembly.

  29. Remove the torque converter to flywheel bolts.
  30. Lower the vehicle.
  31. Attach a suitable lifting hook and a chain to the engine lifting bracket.
  32. Raise the engine slightly in order to take weight off of the mounts.
  33. Remove the torque axis engine mount.
  34. Support the transaxle.
  35. Remove the engine to transaxle bolts.
  36. Separate the engine from the transaxle.
  37. Raise the engine.

Installation Procedure
  1. Lower the engine.
  2. Install the engine to transaxle bolts.
  3. Install the torque axis engine mount.
  4. Raise the vehicle. Support the vehicle suitably.
  5. Install the torque converter to flywheel bolts. Ensure that the relationship between the converter and the flywheel is the same as it was prior to disassembly.
  6. Install the starter motor. Refer to Starter Motor Replacement in Engine Electrical.
  7. Install the flywheel cover.
  8. Install the engine to the transaxle bracket.
  9. Install the A/C compressor. Refer to Compressor Replacement in Heating, Ventilation and Air Conditioning.
  10. Install the exhaust pipe to the right manifold.
  11. Lower the vehicle.
  12. Install the brake booster hose to the engine vacuum connections.
  13. Install the heater control hoses to the engine vacuum connections.
  14. Install the emission control canister hoses to the throttle body connections.
  15. Connect the fuel feed and return lines to the fuel rail. Connect the fuel lines to the fuel pressure regulator.
  16. Install the ignition coil ground strap to the fender inner panel.
  17. Install the wiring harness connectors to the following locations:
    18. • The MAT sensor
    • The throttle position sensor
    • The idle air control valve
    • The oxygen sensor
    • The A/C compressor
    • The oil pressure switch
    • The power steering cutout switch
    • The vehicle speed sensor (VSS)
    • The low oil level sensor
  18. Connect the throttle cable to the throttle linkage.
  19. Install the mounting bracket.
  20. Connect the other applicable cables.
  21. Install the air flow duct.
  22. Install the power steering pump to the engine. Refer to Power Steering Pump Replacement in Power Steering Systems.
  23. Install the drive belt.
  24. For supercharged engines, install the supercharger drive belt.
  25. Install the engine harness connector to the bulkhead.
  26. Connect the negative battery cable to the engine block.
  27. Install the radiator supply hoses.
  28. Install the heater supply hoses.
  29. Refill the coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  30. Refill the engine oil. Refer to Engine Mechanical Specifications .
  31. Connect the negative battery cable.
  32. Check for the proper oil level.
  33. Check the fluid levels.
  34. Inspect for fluid leaks.
  35. Inspect for the proper completion of repairs.
  36. Install the hood. Refer to Hood Replacement in Body Front End.