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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1015 (ENGINE MECHANICAL - 4.3L)REPAIR INSTRUCTIONSON-VEHICLE REPAIR INSTRUCTIONSENGINE REPLACEMENTINSTALLATION PROCEDURE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Installation Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Installation Procedure
WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Install the engine.
    NOTE: Refer to Fastener Notice in Cautions and Notices.
  2. Install the engine mount to engine mount bracket bolts.

    Tighten:  Tighten the bolts to 65 N.m (48 lb ft).

    3. Fig 1: Installing Engine Mount To Engine Mount Bracket Nuts
    GM310259Courtesy of GENERAL MOTORS CORP.
  3. Remove the lifting devise and the J 41427.
    4. Fig 2: Engine Lift Brackets J 41427
    GM33636Courtesy of GENERAL MOTORS CORP.
  4. Apply threadlock GM P/N 12345382, (Canadian P/N 10953489), or equivalent to the threads of the intake manifold lower bolts.
  5. Install the intake manifold bolts.

    Tighten: 

    1. Tighten the bolts a first pass to 3 N.m (27 lb in).
    2. Tighten the bolts a second pass to 12 N.m (106 lb in).
    3. Tighten the bolts a final pass to 15 N.m (11 lb ft).

  6. Install one transmission bolt until snug.
  7. Remove the support jack from under the transmission.
  8. Install the thermostat and water outlet. Refer to Thermostat Replacement (4.3L Engine) in Engine Cooling.
  9. Slide the P/S pump bracket onto the stud.
  10. Install the bolts and the nut for the P/S pump bracket.
  11. Install the P/S pump rear bracket front nut.
  12. Tighten the P/S pump rear bracket nut.

    Tighten:  Tighten the bolts and nuts to 41 N.m (30 lb ft).

    13. Fig 3: View Of Power Steering Pump Bracket
    GM340090Courtesy of GENERAL MOTORS CORP.
  13. Connect the power brake booster vacuum hose to the vacuum fitting.
    14. Fig 4: Connecting Power Brake Booster Vacuum Hose
    GM869713Courtesy of GENERAL MOTORS CORP.
  14. Connect the EVAP canister harness to the purge solenoid valve.
    15. Fig 5: Connecting EVAP Canister Harness
    GM869711Courtesy of GENERAL MOTORS CORP.
  15. Install the distributor cap. Refer to Distributor Replacement in Engine Controls - 4.3L.
  16. Install the heater hoses. Refer to Heater Hose Replacement - Inlet (LU3) and Heater Hose Replacement - Outlet (LU3) in Heating, Ventilation, and Air Conditioning.
  17. Position the engine wiring harness.
  18. Install the stud holding the engine wiring harness bracket.
  19. Install the engine wiring harness rear bracket nut at the EVAP canister purge solenoid valve.

    Tighten:  Tighten the nut to 9 N.m (80 lb in).

    20. Fig 6: Installing Engine Wiring Harness bracket Stud & Engine wiring Harness Rear Bracket Nut
    GM782176Courtesy of GENERAL MOTORS CORP.
  20. Position the bracket and wiring harness.
  21. Install the junction block bracket bolt.

    Tighten:  Tighten the bolt to 25 N.m (18 lb ft).

    22. Fig 7: Installing Junction Block Bracket Bolt
    GM782670Courtesy of GENERAL MOTORS CORP.
  22. Install the engine wiring harness bracket to the studs.
  23. Install the engine wiring harness bracket nuts.

    Tighten:  Tighten the nuts to 12 N.m (106 lb in).

    24. Fig 8: Installing Engine Wiring Harness Bracket Nuts
    GM310241Courtesy of GENERAL MOTORS CORP.
  24. Position the harness ground (4) and ground strap (5).
  25. Install the harness ground bolt.

    Tighten:  Tighten the bolt to 16 N.m (12 lb ft).

  26. Connect the following electrical connectors:
    • Knock sensor (1)
    • CMP sensor (2)
    • Fuel pump/oil pressure sensor (3)
    • Distributor (2)
    27. Fig 9: View Of Ground Strap And CMP & Fuel Pump/Oil Pressure Sensor Connectors
    GM782680Courtesy of GENERAL MOTORS CORP.
  27. Install the engine wiring harness ground nut and ground wire (4) to the rear of the right cylinder head.

    Tighten:  Tighten the nut to 16 N.m (12 lb ft).

  28. Connect the following electrical connectors:
    • Ignition coil (1)
    • Ignition coil driver (2)
    • Generator (3)
    29. Fig 10: Ignition Coil, Ignition Coil Driver, Ground Nut/Cable & Generator Electrical Connectors
    GM782177Courtesy of GENERAL MOTORS CORP.
  29. Connect the following electrical connectors:
    • EVAP canister purge solenoid valve (1)
    • MAP sensor (2)
    30. Fig 11: EVAP Canister Purge Solenoid Valve & MAP Sensor
    GM782178Courtesy of GENERAL MOTORS CORP.
  30. Install the engine wiring harness clip bolt (4).

    Tighten:  Tighten the bolt to 9 N.m (80 lb in).

  31. Connect the following electrical connectors:
    • TP sensor (1)
    • IAC motor (2)
    • Control port injector module (3)
    • ECT sensor (5)
    32. Fig 12: View Of TP Sensor, IAC Motor, ECT Sensor, Control Port Injector Module & Engine Harness Clip Bolt
    GM782174Courtesy of GENERAL MOTORS CORP.
  32. Install the positive cable and nut to the generator.

    Tighten:  Tighten the nut to 18 N.m (13 lb ft).

  33. Connect the following electrical connectors:
    • A/C pressure switch (4), if equipped
    • A/C compressor clutch (1), if equipped
    34. Fig 13: A/C Pressure Switch & Compressor Clutch
    GM782175Courtesy of GENERAL MOTORS CORP.
  34. If equipped, install the A/C hoses. Refer to Discharge Hose Replacement (LB7) or Discharge Hose Replacement (LR4,LM7,LQ4,L18) and Suction Hose Replacement (LB7 w/Denso) or Suction Hose Replacement (LR4, LM7, LQ4, L18 w/Denso) in Heating, Ventilation, and Air Conditioning.
  35. Position the bracket and cables.
  36. Install the accelerator control cable bracket with the cables attached, to the throttle body.
  37. Install the accelerator control cable bracket nuts.

    Tighten:  Tighten the nuts to 9 N.m (80 lb in).

    38. Fig 14: View Of Accelerator Control Cable Bracket
    GM398030Courtesy of GENERAL MOTORS CORP.
  38. Install the accelerator cable to the throttle body lever.
    39. Fig 15: Identifying Accelerator Cable/Throttle Body Lever
    GM325556Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.