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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1439 (ENGINE MECHANICAL - 5.3L (LM4))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 Envoy XUV, 2004 GMC Envoy XL, 2004 Chevrolet TrailBlazer, and 2004 Buick Rainier. However, it is still accessible from the selected car via links, so may be relevant.
    Fig 1: View Of Automatic Transmission Bolt/Studs
    GM859003Courtesy of GENERAL MOTORS CORP.
  1. Remove the J 21366  from the transmission. See Special Tools and Equipment .
  2. Install an engine hoist to the J 41798  . See Special Tools and Equipment .
  3. Remove the engine from the engine stand.
  4. Install the engine.
  5. Mate the engine to the transmission.
  6. Remove the floor jack from under the transmission for support.
    NOTE: Refer to Fastener Notice in Cautions and Notices.
  7. Install the 3 upper transmission bolts/studs.

    Tighten:  Tighten the bolts/studs to 50 N.m (37 lb ft).

  8. Raise the vehicle.
  9. Install the lower transmission bolt/studs.

    Tighten:  Tighten the bolts/studs to 50 N.m (37 lb ft).

    10. Fig 2: View of Transmission Bolt & Stud
    GM859004Courtesy of GENERAL MOTORS CORP.
  10. Install the transmission bolt and stud on the right side.

    Tighten:  Tighten the bolts/studs to 50 N.m (37 lb ft).

    11. Fig 3: View Of Oil Level Indicator Tube & Seal
    GM396798Courtesy of GENERAL MOTORS CORP.
  11. Install the transmission oil level indicator tube.
    12. Fig 4: View Of Oil Level Indicator Tube Nut
    GM396797Courtesy of GENERAL MOTORS CORP.
  12. Install the transmission oil level indicator tube nut.

    Tighten:  Tighten the nut to 10 N.m (89 lb ft).

    13. Fig 5: Flywheel-To-Torque Converter Bolts
    GM9096Courtesy of GENERAL MOTORS CORP.
  13. Install the torque converter bolts.

    Tighten:  Tighten the bolts to 60 N.m (44 lb ft).

    14. Fig 6: View Of Frame Engine Mount Bracket Bolt Locations
    GM876704Courtesy of GENERAL MOTORS CORP.
  14. Install the 3 frame engine mount bracket bolts to both the right and left sides.

    Tighten:  Tighten the bolts to 50 N.m (37 lb ft).

  15. Install the catalytic converter. Refer to Catalytic Converter Replacement (5.3L Engine) in Engine Exhaust.
  16. Lower the vehicle.
    17. Fig 7: View Of J 41798
    GM309151Courtesy of GENERAL MOTORS CORP.
  17. Remove the J 41798  from the cylinder heads. See Special Tools and Equipment .
  18. Install the ignition coil(s) (as required).

    Tighten:  Tighten the bolts to 8 N.m (71 lb in).

    19. Fig 8: View Of Auxiliary Heater Inlet & Outlet Hoses/Pipes
    GM901492Courtesy of GENERAL MOTORS CORP.
  19. Install the auxiliary heater inlet and outlet hoses/pipes to the water pump.
  20. Using J 38185  , reposition the auxiliary heater inlet and outlet hose clamps. See Special Tools and Equipment .
    21. Fig 9: Disconnecting/Connecting Auxiliary Heater Hose/Pipe Assembly
    GM901493Courtesy of GENERAL MOTORS CORP.
  21. Connect the auxiliary heater inlet and outlet hose/pipe assembly to the heater water shutoff valve pipes.
    22. Fig 10: View Of Outlet Hose
    GM901491Courtesy of GENERAL MOTORS CORP.
  22. Install the outlet hose to the water outlet.
  23. Using J 38185  , reposition the inlet hose clamp. See Special Tools and Equipment .
    24. Fig 11: View Of Inlet Hose
    GM901490Courtesy of GENERAL MOTORS CORP.
  24. Install the inlet hose to the water outlet.
  25. Using J 38185  , reposition the inlet hose clamp. See Special Tools and Equipment .
    26. Fig 12: View Of Generator Bracket & Bolts
    GM310813Courtesy of GENERAL MOTORS CORP.
  26. Position the bracket with generator to the engine.
  27. Install the generator bracket bolts.

    Tighten:  Tighten the bolts to 50 N.m (37 lb ft).

    28. Fig 13: View Of Generator Cable & Nut
    GM395686Courtesy of GENERAL MOTORS CORP.
  28. Install the generator cable to the generator, perform the following:
    • Install the generator cable.
    • Install the generator cable nut to the terminal stud.

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

    • Slide the boot down covering the terminal stud.
    29. Fig 14: Disconnecting/Connecting A/C Compressor Electrical Connector
    GM898469Courtesy of GENERAL MOTORS CORP.
  29. Gather all branches of the engine wiring harness and position the harness over the engine.
  30. Raise the vehicle.
  31. Connect the A/C compressor electrical connector.
    32. Fig 15: View Of Battery Cable Channel & Bolt
    GM899616Courtesy of GENERAL MOTORS CORP.
  32. Install the battery cable channel to the oil pan.
  33. Install the battery cable channel bolt.

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

    34. Fig 16: View Of Ground Terminal Bolts
    GM898338Courtesy of GENERAL MOTORS CORP.
  34. Install the starter. Refer to Starter Motor Replacement (5.3L Engine) in Engine Electrical.
  35. Install the ground terminal bolts (2, 4).

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

  36. Lower the vehicle.
    37. Fig 17: View Of A/C Compressor Pressure Switch Electrical Connector & Retaining Clip
    GM898468Courtesy of GENERAL MOTORS CORP.
  37. Install the retaining clip (1) to the cylinder head.
  38. Connect the A/C pressure switch electrical connector (2).
    39. Fig 18: View Of ECT Sensor Electrical Connector And Ground
    GM898343Courtesy of GENERAL MOTORS CORP.
  39. Install the retaining clips to the brackets.
  40. Install the ground terminal bolt (2).

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

  41. Connect the ECT sensor (1).
    42. Fig 19: View Of Rear A/C Lines
    GM871567Courtesy of GENERAL MOTORS CORP.
  42. Install the rear auxiliary A/C compressor pipe nut and bolt (2, 5).

    Tighten:  Tighten the nut/bolt to 20 N.m (15 lb ft).

  43. Connect the rear auxiliary A/C compressor pipe fitting (7).

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

  44. Install the A/C compressor hose. Refer to Compressor Hose Assembly Replacement (LM4) in Heating, Ventilation, and Air Conditioning.
    45. Fig 20: Locating Components Connectors At Rear Of Engine
    GM898333Courtesy of GENERAL MOTORS CORP.
  45. Connect the following electrical connectors:
    • Oil pressure sensor (1)
    • Oxygen sensors (2, 3)
    • Camshaft position (CMP) sensor (4)
  46. Install the intake manifold. Refer to Intake Manifold Replacement  .
  47. Install the wheel drive shafts. Refer to Wheel Drive Shaft Replacement in Wheel Drive Shafts.
  48. Install the front differential drive axle, if equipped with 4WD. Refer to Differential Carrier Assembly Replacement (4.8L, 5.3L, 6.0L V-8) in Front Drive Axle.
  49. Install the radiator support brace. Refer to Brace Replacement - Radiator Support Diagonal in Body Front End.
  50. Install the radiator. Refer to Radiator Replacement (LM4) in Engine Cooling.
  51. Recharge the refrigerant. Refer to Refrigerant Recovery and Recharging in Heating, Ventilation, and Air Conditioning.
  52. Connect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  53. Remove the fender covers from both fenders.
  54. Prelube the engine. Refer to Engine Prelubing  .
  55. Perform the CKP system variation learn procedure. Refer to CKP System Variation Learn Procedure in Engine Controls - 4.8L, 5.3L, and 6.0L.
  56. Install the hood. Refer to Hood Replacement in Body Front End.
    IMPORTANT: After an overhaul, the engine should be tested. Use the following procedure after the engine is installed in the vehicle.
  57. Test the vehicle using the following procedure:
    • Disable the ignition system.
    • Crank the engine several times. Listen for any unusual noises or evidence that parts are binding.
    • Enable the ignition system.
    • Start the engine and listen for unusual noises.
    • Check the vehicle oil pressure gauge or light and confirm that the engine has acceptable oil pressure.
    • Run the engine speed at about 1000 RPM until the engine has reached normal operating temperature.
    • Listen for sticking lifter and other unusual noises.
    • Inspect for fuel, oil and/or coolant leaks while the engine is running.
    • Close the hood.
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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.