GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C-Series Medium Duty Truck B7 🢒 Engine 🢒 Engine Mechanical - 7.2L (Caterpillar) 🢒 Engine Replacement

Removal Procedure

    Object Number: 198949 Size: SH
  1. Disconnect the negative battery cables from the batteries. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Remove the hood from the vehicle. Refer to Hood Replacement in Body Front End.
  3. Remove the left and right wheel house panel from the vehicle. Refer to Wheelhouse Panel Replacement in Body Front End.
  4. Remove the air intake duct (1) from the from the air cleaner.

    5. Object Number: 587865 Size: SH

    Important: Cover the turbocharger openings with duct tape or any other suitable cover in order to prevent any foreign objects from falling into the turbocharger. This will prevent any damage from occurring to the turbocharger.

  5. Remove the air cleaner assembly from the mounting bracket.

    6. Object Number: 587864 Size: SH
  6. Remove the air cleaner mounting bracket from the engine block.

    7. Object Number: 587867 Size: SH
  7. Remove the air outlet duct between the turbocharger and the air cleaner housing.

    8. Object Number: 587868 Size: SH
  8. Remove the outlet air duct between the turbochargers and the charged air cooler.

    9. Object Number: 587882 Size: SH
  9. Remove the charged air cooler outlet duct from charged air cooler and the intake manifold.
  10. Disconnect the power steering lines from the power steering pump and allow to drain in a suitable drain pan.
  11. Drain the crankcase. Refer to Caterpillar® 3126 Unit Repair Manual.
  12. Drain the engine cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  13. Drain the air reservoirs for the air brakes. Refer to Draining Reservoirs in Air Brakes.

    14. Object Number: 200514 Size: SH
  14. Disconnect the discharge line from the air compressor.

    15. Object Number: 200515 Size: SH
  15. Remove the governor air line from the air compressor.

    16. Object Number: 200516 Size: SH
  16. Remove the air inlet line from the air compressor.

    17. Object Number: 580776 Size: SH
  17. Remove the engine wiring harness from the retainers, left side only.
  18. Disconnect the electrical connectors from the following items:
    19. • The oil pressure sensor
    • The low oil pressure switch
    • The ECU (Engine Control Unit)
    • The coolant temperature sensor

    Object Number: 580770 Size: SH
  19. Remove the electrical connectors from the following items:
    20. • The shutdown switch
    • The coolant temperature switch

    Object Number: 580931 Size: SH
  20. Remove the engine wiring harness from the retainers, right side only.

    21. Object Number: 580764 Size: SH
  21. Remove the electrical connectors from the heated air intake relay.

    22. Object Number: 204739 Size: SH
  22. Remove the ground strap from the frame to the starter.
  23. Remove the starter from the vehicle. Refer to Starter Motor Replacement in Engine Electrical.
  24. Secure the engine wiring harness out of the way.

    25. Object Number: 201609 Size: SH
  25. Remove the transmission oil level indicator and the tube, AT 545 and MTS transmission.

    26. Object Number: 201611 Size: SH
  26. Remove the transmission oil level indicator and the tube, MD series transmission.
  27. Remove the radiator from the vehicle. Refer to Radiator Replacement in Engine Cooling.

    28. Object Number: 587870 Size: SH
  28. Remove the transmission cooler lines from the retainer.

    29. Object Number: 201569 Size: SH
  29. Remove the transmission oil cooler lines from the retainer and secure out of the way.
  30. Remove the lower radiator panel from the vehicle.
  31. Remove the radiator inlet hose from the engine assembly. Refer to Radiator Inlet Hose Replacement in Engine Cooling.
  32. Remove the radiator outlet hose from the engine assembly. Refer to Radiator Outlet Hose Replacement in Engine Cooling.

    33. Object Number: 213161 Size: SH
  33. Disconnect the exhaust pipe from the turbocharger.

    34. Object Number: 9096 Size: SH
  34. Remove the torque convertor bolts from the torque convertor.

    35. Object Number: 201539 Size: SH
  35. Remove the vacuum modulator vacuum line, for automatic transmission only.

    36. Object Number: 580768 Size: SH
  36. Disconnect the fuel lines at the rear of the engine.
  37. Support the transmission with a suitable transmission support.
  38. Attach a suitable lifting device to the engine assembly.

    39. Object Number: 205284 Size: SH
  39. Remove the bolts from the transmission to the engine block.

    40. Object Number: 572364 Size: SH
  40. Remove the engine mount through bolts from the engine mounts.
  41. Remove the engine from the vehicle.

    42. Important: It maybe necessary to remove the clutch or the flywheel from the engine assembly before installing the engine assembly on the engine stand.

  42. Remove the clutch, if equipped, from the flywheel. Refer to Clutch Assembly Replacement in Clutch.
  43. Remove the flywheel from the engine assembly. Refer to Caterpillar® 3126 Unit Repair Manual.
  44. Install the engine on a suitable engine stand.
  45. Remove the lifting device from the engine assembly.

Installation Procedure

    Object Number: 201597 Size: SH
  1. Install the lifting device to the engine assembly.
  2. Remove the engine assembly from the engine stand.
  3. Install the flywheel to the crankshaft. Refer to Caterpillar® 3126 Unit Repair Manual.
  4. Install the clutch, if equipped, to the flywheel. Refer to Caterpillar® 3126 Unit Repair Manual.
  5. Install the engine assembly in the vehicle.

    6. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  6. Install the bolts from the transmission to the engine block, manual transmission.

    7. Tighten
    Tighten the bolts to 54 N·m (40 lb ft).

  7. Install the bolts from the transmission to the engine block, automatic transmission.

    8. Tighten
    Tighten the bolts to 58 N·m (43 lb ft).

  8. Lower the engine on the front engine mount brackets.

    9. Object Number: 572364 Size: SH
  9. Install the engine mount through bolts.

    10. Tighten
    Tighten the through bolts to 54 N·m (40 lb ft).

  10. Remove the lifting device from the engine assembly.
  11. Remove the transmission support.

    12. Object Number: 201539 Size: SH
  12. Install the vacuum line for the modulator valve.

    13. Object Number: 580768 Size: SH
  13. Connect the fuel lines at the rear of the engine.

    14. Object Number: 9096 Size: SH
  14. Install the bolts from the flywheel to the torque convertor.

    15. Tighten
    Tighten the torque convertor bolts to 67 N·m (49 lb ft).

  15. Install the starter motor to the engine block. Refer to Starter Motor Replacement in Engine Electrical.

    16. Object Number: 204739 Size: SH
  16. Install the ground strap from the frame to the starter.

    17. Tighten
    Tighten the retaining nuts to 27 N·m (20 lb ft).

  17. Install the exhaust pipe to the turbocharger.

    18. Object Number: 580764 Size: SH
  18. Install the electrical connectors for the heated air intake relay.

    19. Tighten
    Tighten the retaining nut to 22 N·m (16 lb ft).


    Object Number: 580931 Size: SH
  19. Install the wiring harness on the right front of the engine block to the retainers.

    20. Tighten

        • Tighten the mounting bolts to 45 N·m (33 lb ft).
        • Tighten the retaining nuts to 22 N·m (16 lb ft).

    Object Number: 580770 Size: SH
  20. Install the electrical connectors to the following items:
    21. • Shutdown switch
    • Coolant temperature switch
  21. Install the engine wiring harness to the retainers.

    22. Tighten
    Tighten the mounting bolt to 45 N·m (33 lb ft).


    Object Number: 580776 Size: SH
  22. Install the electrical connectors to the following items:
    23. • The oil pressure sensor
    • The low oil pressure switch
    • The ECU (Engine Control Unit)
    • The coolant temperature sensor
  23. Install the wiring harness to the retainers.

    24. Tighten
    Tighten the retaining bolts to 22 N·m (16 lb ft).

  24. Install the radiator inlet hose to the engine assembly. Refer to Radiator Inlet Hose Replacement in Engine Cooling.
  25. Install the radiator outlet hose to the engine assembly. Refer to Radiator Outlet Hose Replacement in Engine Cooling.
  26. Install the lower radiator panel in the vehicle.
  27. Install the radiator in the vehicle. Refer to Radiator Replacement in Engine Cooling.

    28. Object Number: 587870 Size: SH
  28. Install the transmission lines to the retainer.

    29. Tighten
    Tighten the retaining bolt to 30 N·m (22 lb ft).


    Object Number: 201609 Size: SH
  29. Install the transmission oil level indicator and tube to the engine assembly, AT 545 and MTS transmission.

    30. Tighten
    Tighten the retaining bolt to 20 N·m (15 lb ft).


    Object Number: 201611 Size: SH
  30. Install the transmission oil level indicator and tube to the engine assembly, MD series transmission.

    31. Tighten
    Tighten the retaining bolt to 20 N·m (15 lb ft).


    Object Number: 200516 Size: SH
  31. Install the air inlet hose to the air compressor.

    32. Object Number: 200515 Size: SH
  32. Install the governor air line to the air compressor.

    33. Object Number: 200514 Size: SH
  33. Install the discharge air line to the air compressor.
  34. Install the lines to the power steering pump.

    35. Object Number: 587864 Size: SH
  35. Install the air cleaner housing mounting bracket to the cylinder head.

    36. Tighten
    Tighten the mounting bolts to 10 N·m (89 lb in).

  36. Remove the covers from the turbocharger openings.

    37. Object Number: 587882 Size: SH
  37. Install the outlet duct from the charged air cooler to the intake manifold.

    38. Object Number: 587868 Size: SH
  38. Install the outlet duct from the turbocharger to the charged air cooler.

    39. Object Number: 587867 Size: SH
  39. Install the duct from the turbocharger to the air cleaner housing.

    40. Object Number: 587865 Size: SH
  40. Install the air cleaner housing to the mounting bracket.

    41. Tighten
    Tighten the mounting bolts to 45 N·m (33 lb ft).


    Object Number: 198949 Size: SH
  41. Install the duct (1) from the air cleaner to the air intake.
  42. Install the left and right wheel house panels to the vehicle. Refer to Wheelhouse Panel Replacement in Body Front End.
  43. Install the hood on the vehicle. Refer to Hood Replacement in Body Front End.
  44. Connect the battery negative cables to the batteries. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  45. Fill the engine crankcase with the proper grade and type of engine oil. Refer to Approximate Fluid Capacities in Maintenance and Lubrication.
  46. Fill the cooling system with the proper type and quantity of engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  47. Fill the power steering reservoir to the proper level. Refer to Approximate Fluid Capacities in Maintenance and Lubrication.
  48. Fill the air brake reservoir with air. Refer to Filling Reservoirs in Air Brakes.
  49. Bleed the power steering if necessary.
    50. • For vehicles equipped with the remote reservoir, refer to Power Steering System Bleeding in Power Steering.
    • For vehicles equipped with the integral reservoir, refer to Power Steering System Bleeding in Power Steering.
  50. Prime the lubrication oil galleries if the engine has been rebuilt. Refer to Caterpillar® 3126 Unit Repair Manual.
  51. Prime the engine oil system if the engine has been rebuilt. Refer to Caterpillar® 3126 Unit Repair Manual.
  52. Prime the fuel system before starting the engine. Refer to Caterpillar® 3126 Unit Repair Manual.