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For 1990-2009 cars only

Exhaust Manifold Replacement - Left Side 4.3L Engine

Removal Procedure


    Object Number: 858550  Size: SH
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Remove the exhaust manifold pipe nuts.
  3. Lower the vehicle.

  4. Object Number: 317450  Size: SH
  5. Disconnect the spark plug wires from the spark plugs.
  6. Remove the spark plug wire retainer bolts.
  7. Position the wire harness on top of the engine.

  8. Object Number: 14824  Size: SH
  9. Remove the spark plugs.

  10. Object Number: 782174  Size: SH
  11. Disconnect the engine coolant temperature (ECT) sensor electrical connector (5).

  12. Object Number: 188045  Size: SH
  13. Remove the exhaust manifold and spark plug wire shields bolts/stud.
  14. Remove the exhaust manifold and plug wire shields.

  15. Object Number: 328540  Size: SH
  16. Remove and discard the exhaust manifold gaskets.

  17. Object Number: 493850  Size: SH
  18. Remove the exhaust manifold heat shield bolts and shield, if required.
  19. Clean all gasket mating surfaces.

Installation Procedure


    Object Number: 493850  Size: SH

    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.

  1. Install the exhaust manifold heat shield and bolts, if required.
  2. Tighten
    Tighten the bolts to 9 N·m (80 lb in).


    Object Number: 476818  Size: SH

    Important: To assist in installing the exhaust manifold and gasket to the engine, tabs on a NEW exhaust manifold gasket will hold the gasket and bolts in place.

  3. Install NEW exhaust manifold gaskets to the exhaust manifold.
  4. Ensure that the exhaust manifold bolts/stud, and plug wire shields are held in place by the tabs on the exhaust manifold gaskets.

  5. Object Number: 188045  Size: SH
  6. Install the exhaust manifold and plug wire shields.
  7. If reusing the old fasteners, apply threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts/stud.
  8. Tighten the exhaust manifold bolts/stud.
  9. Tighten
    Tighten the bolts/stud to 30 N·m (22 lb ft).


    Object Number: 782174  Size: SH
  10. Connect the ECT sensor electrical connector (5).

  11. Object Number: 14824  Size: SH
  12. Install the spark plugs.
  13. Tighten
    Tighten the plugs to 15 N·m (11 lb ft).


    Object Number: 317450  Size: SH
  14. Position the wire harness to the engine.
  15. Install the spark plug wire retainer bolts.
  16. Tighten
    Tighten the bolts to 12 N·m (106 lb in).

  17. Connect the spark plug wires to the spark plugs.
  18. Raise the vehicle.

  19. Object Number: 858550  Size: SH
  20. Install the exhaust manifold pipe nuts.
  21. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).

  22. Lower the vehicle.

Exhaust Manifold Replacement - Left Side 4.8L, 5.3L, and 6.0L Engine

Removal Procedure


    Object Number: 858550  Size: SH
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Remove the exhaust manifold pipe nuts.
  3. Lower the vehicle.
  4. Remove the spark plugs. Refer to Spark Plug Replacement .

  5. Object Number: 858556  Size: SH
  6. Remove the exhaust manifold bolts, manifold, and gasket.
  7. Discard the gasket.

  8. Object Number: 492766  Size: SH
  9. Remove the heat shield bolts (3), and shield (2) from the exhaust manifold (1), if necessary.
  10. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection .

Installation Procedure


    Object Number: 492766  Size: SH

    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.

  1. Install the heat shield (2), and bolts (3) to the exhaust manifold (1), if necessary.
  2. Tighten
    Tighten the bolts to 9 N·m (80 lb in).


    Object Number: 858556  Size: SH

    Important: 

       • Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or On-Board Diagnostics (OBD) II system performance.
       • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.

    Important: Do not apply sealant to the first three threads of the bolt.

  3. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
  4. Install the exhaust manifold, NEW gasket and bolts.
  5. Tighten

    1. Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
    2. Tighten the bolts a final pass to 25 N·m (18 lb ft). Tighten the bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
  6. Using a flat-punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
  7. Install the spark plugs. Refer to Spark Plug Replacement .
  8. Raise the vehicle.

  9. Object Number: 858550  Size: SH
  10. Install the exhaust manifold pipe nuts.
  11. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).

  12. Lower the vehicle.

Exhaust Manifold Replacement - Left Side 6.6L Engine

Removal Procedure


    Object Number: 1334829  Size: SH
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Remove the exhaust pipe heat shield bolts.
  3. Reposition the heat shield to the side in order to access the exhaust pipe to exhaust manifold bolts.

  4. Object Number: 721427  Size: SH
  5. Lower the vehicle in order to work through the front wheelhouse opening.
  6. Remove the wheelhouse panel. Refer to Wheelhouse Panel Replacement .
  7. Remove the charged air cooler outlet duct. Refer to Charged Air Cooler Hoses/Pipes Replacement .
  8. Remove the exhaust pipe to exhaust manifold bolts (1, 2, and 3).

  9. Object Number: 1335937  Size: SH
  10. Remove the exhaust manifold heat shield bolts.
  11. Remove the exhaust manifold heat shield.

  12. Object Number: 1335939  Size: SH
  13. Remove the exhaust manifold bolts and nuts in the proper sequence.

  14. Object Number: 1336105  Size: SH
  15. Remove the exhaust manifold.
  16. Remove and discard the exhaust manifold gasket.
  17. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection .

Installation Procedure


    Object Number: 1336105  Size: SH
  1. Install the exhaust manifold with gasket.
  2. Install the exhaust manifold bolts/nuts.
  3. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1335939  Size: SH
  4. Use the sequence shown to properly tighten the exhaust manifold bolts.
  5. Tighten
    Tighten the bolts/nut to 38 N·m (28 lb ft).


    Object Number: 1335937  Size: SH
  6. Install the exhaust manifold heat shield.
  7. Install the exhaust manifold heat shield bolts.
  8. Tighten
    Tighten the bolts to 8 N·m (71 lb in).


    Object Number: 721427  Size: SH
  9. Install the exhaust pipe gasket. Align the tab on the gasket to face outward.
  10. Install the exhaust pipe and the bolts (1, 2, and 3) to the exhaust manifold.
  11. Tighten
    Tighten the bolts to 53 N·m (39 lb ft).


    Object Number: 1334829  Size: SH
  12. Raise the vehicle.
  13. Install the exhaust pipe heat shield bolts.
  14. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  15. Install the charged air cooler outlet duct. Refer to Charged Air Cooler Hoses/Pipes Replacement .
  16. Install the wheelhouse panel. Refer to Wheelhouse Panel Replacement .
  17. Lower the vehicle.

Exhaust Manifold Replacement - Left Side 8.1L Engine

Removal Procedure


    Object Number: 470666  Size: SH
  1. Remove the wheelhouse panel. Refer to Wheelhouse Panel Replacement .
  2. Important: Twist the spark plug boot one-half turn in order to release the boot. Pull on the spark plug boot only. Do not pull on the spark plug wire or the wire could be damaged.

  3. Remove the spark plug wires from the spark plugs and ignition coils.
  4. Remove the spark plugs. Refer to Spark Plug Replacement .

  5. Object Number: 858561  Size: SH
  6. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  7. Remove the exhaust manifold heat shield bolts and nuts.
  8. Remove the left exhaust manifold heat shield.
  9. Lower the vehicle.

  10. Object Number: 470679  Size: SH
  11. Remove the exhaust manifold bolt and nuts.
  12. Remove the exhaust manifold.
  13. Remove and discard the exhaust manifold gasket.
  14. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection .

Installation Procedure


    Object Number: 470679  Size: SH
  1. Install a NEW exhaust manifold gasket.
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the exhaust manifold.
  4. Install the exhaust manifold bolt and nuts.
  5. Tighten

        • Tighten the bolt to 35 N·m (26 lb ft).
        • Tighten the nuts to 16 N·m (12 lb ft).
  6. Raise the vehicle.

  7. Object Number: 858561  Size: SH
  8. Install the exhaust manifold heat shield.
  9. Install the exhaust manifold heat shield bolts and nuts.
  10. Tighten
    Tighten the bolts and nuts to 25 N·m (18 lb ft).

  11. Lower the vehicle.
  12. Install the spark plugs. Refer to Spark Plug Replacement .

  13. Object Number: 470666  Size: SH

    Important: Fully install the spark plug wire by pushing on the exposed end of the spark plug boot. Do not push the spark plug wire on to the spark plug by using the metal heat shield.

  14. Install the spark plug wires to the spark plugs and ignition coils.
  15. Install the wheelhouse panel. Refer to Wheelhouse Panel Replacement .