H3 2006

Exhaust Manifold

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Removal & Installation



3.5L & 3.7L Engines
  1. Remove the exhaust seal, as follows:
    1. Raise and support the vehicle.
    2.  
    3. Remove the 3 nuts attaching the catalytic converter to the exhaust manifold.
    4.  
    5. Position the exhaust system rearward, enough to allow clearance to remove the seal.
    6.  
    7. Remove the exhaust manifold seal from the exhaust manifold flange. Discard the seal.
    8.  

  2.  
  3. Remove the exhaust manifold heat shield, as follows:
    1. Remove the air cleaner outlet duct.
    2.  
    3. Remove the air cleaner assembly.
    4.  
    5. If equipped with A/T, remove the transmission filler tube bracket nut from the A.I.R. adapter, and position aside.
    6.  
    7. Remove the Heated Oxygen Sensor (HO2S) from the exhaust manifold.
    8.  
    9. Remove the 3 nuts securing the heat shield to the exhaust manifold.
    10.  
    11. Remove the heat shield.

      Click image to see an enlarged view

      Fig. Exhaust manifold heat shield

    12.  

  4.  
  5. Remove the exhaust manifold bolts.
  6.  
  7. Remove the exhaust manifold and the gasket from the engine. Discard the gasket.

    Click image to see an enlarged view

    Fig. Exhaust manifold gasket

  8.  

To install:

  1. Place a NEW exhaust manifold gasket on to the cylinder head.
  2.  
  3. Position the exhaust manifold to the cylinder head.
  4.  
  5. Apply thread lock GM P/N 12345493 (Canadian P/N 10953488) to the exhaust manifold bolt threads.
  6.  
  7. Install the exhaust manifold bolts.
  8.  
  9. Tighten the exhaust manifold bolts in sequence to 15 ft. lbs. (20 Nm).

    Click image to see an enlarged view

    Fig. Exhaust manifold bolt tightening sequence

  10.  
  11. Install the exhaust manifold heat shield, as follows:
    1. Position the heat shield to the exhaust manifold.
    2.  
    3. Apply anti-seize GM P/N 12371386 (Canadian P/N 993128) to the exhaust manifold heat shield nuts.
    4.  
    5. Install the exhaust manifold heat shield nuts and tighten to 89 inch lbs. (10 Nm).
    6.  
    7. Install the HO2S to the exhaust manifold.
    8.  
    9. Position the transmission filler tube to the A.I.R. adapter if previously removed.
    10.  
    11. Install the transmission filler tube bracket nut and tighten to 9 ft. lbs. (12.5 Nm).
    12.  
    13. Install the air cleaner assembly and air cleaner outlet duct.
    14.  

  12.  
  13. Install the exhaust seal, as follows:
    1. Install the NEW seal to the exhaust manifold flange.
    2.  
    3. Position the catalytic converter to the exhaust manifold.
    4.  
    5. Install the 3 nuts attaching the catalytic converter to the exhaust manifold and tighten to 37 ft. lbs. (50 Nm).
    6.  
    7. Lower the vehicle.
    8.  

  14.  

5.3L Engine
Left Side

Specific to:

Hummer H3 2006-2010

  1. Raise and suitably support the vehicle.
  2.  
  3. Remove the left front tire and wheel assembly.
  4.  
  5. Remove the left catalytic converter.
  6.  
  7. Remove the upper intake manifold sight shield, as follows:
    1. Remove the oil fill cap.
    2.  
    3. Grasp the front of the intake manifold sight shield and lift up disengaging the grommets from the studs.
    4.  
    5. Remove the intake manifold sight shield from the retainer slots.
    6.  
    7. Remove the intake manifold sight shield retainer bolts and retainer, if required.

      Click image to see an enlarged view

      Fig. Upper intake manifold sight shield-5.3L engine

    8.  

  8.  
  9. Remove the spark plugs.
  10.  
  11. Remove the exhaust manifold heat shield bolts and heat shield from the exhaust manifold.

    Click image to see an enlarged view

    Fig. Exhaust manifold heat shield -5.3L engine, left side

  12.  
  13. Working through the wheel well opening, remove the exhaust manifold bolts (1).
    NOTE
    The manifold is removed from below the vehicle.

  14.  
  15. Remove the exhaust manifold and gasket. Discard the gasket.

    Click image to see an enlarged view

    Fig. Exhaust manifold (2), bolts (1), and gasket (3)-5.3L engine, left side

  16.  

To install:


WARNING
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.


NOTE
The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or thread locking material.


NOTE
Do not apply sealant to the first 3 threads of the bolt.

  1. Apply a 0.2 inches (5 mm) wide band of thread lock GM P/N 12345493, (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
  2.  
  3. Install one exhaust manifold bolt to the exhaust manifold and place the NEW gasket onto the bolt.
  4.  
  5. Working through the wheel well opening, install the remaining exhaust manifold bolts.
    1. Tighten the bolts a first pass to 11 ft. lbs. (15 Nm). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
    2.  
    3. Tighten the bolts a final pass to 18 ft. lbs. (25 Nm). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
    4.  

  6.  
  7. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
  8.  
  9. Position the exhaust manifold heat shield and bolts to the manifold and tighten to 80 inch lbs. (9 Nm).
  10.  
  11. Install the spark plugs.
  12.  
  13. Install upper intake manifold sight shield, as follows:
    1. Position the intake manifold sight shield on top of the intake manifold, aligning the holes, if required.
    2.  
    3. Install the intake manifold sight shield retainer bolts, if required. Tighten to 44 inch lbs. (5 Nm).
    4.  
    5. Install the intake manifold sight shield tabs into the slots in the retainer.
    6.  
    7. Align the intake manifold sight shield grommets with the studs.
    8.  
    9. Gently push down on the intake manifold sight shield over the grommets, seating the intake manifold sight shield.
    10.  
    11. Install the oil fill cap.
    12.  

  14.  
  15. Install the catalytic converter. Tighten the nuts to 37 ft. lbs. (50 Nm).
  16.  
  17. Install the left front tire and wheel assembly.
  18.  
  19. Lower the vehicle.
  20.  

Right Side

Specific to:

Hummer H3 2006-2010

  1. Raise and suitably support the vehicle.
  2.  
  3. Remove the catalytic converter.
  4.  
  5. Remove the spark plugs.
  6.  
  7. Remove the exhaust manifold heat shield bolts (1) and shield (2).

    Click image to see an enlarged view

    Fig. Exhaust manifold heat shield -5.3L engine, right side

  8.  
  9. Remove the oil level indicator and tube.
  10.  
  11. Remove the exhaust manifold bolts (3).
  12.  
  13. Remove the exhaust manifold (2) and gasket (1). Discard the gasket.

    Click image to see an enlarged view

    Fig. Exhaust manifold (2), bolts (3), and gasket (1)-5.3L engine, right side

  14.  

To install:


NOTE
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.


NOTE
The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or thread locking material.


NOTE
Do not apply sealant to the first 3 threads of the bolt.

  1. Apply a 0.2 in, (5 mm) wide band of thread lock GM P/N 12345493, (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
  2.  
  3. Ensure that the exhaust seal is still seated on the catalytic converter recess.
  4.  
  5. Install one exhaust manifold bolt to the exhaust manifold and place the NEW gasket onto the bolt.
  6.  
  7. Install the exhaust manifold to the catalytic converter flange and position the manifold to the cylinder head.
  8.  
  9. Install the oil level indicator and tube.
  10.  
  11. Install the remaining exhaust manifold bolts.
    1. Tighten the bolts a first pass to 11 ft. lbs. (15 Nm). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
    2.  
    3. Tighten the bolts a final pass to 18 ft. lbs. (25 Nm). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
    4.  

  12.  
  13. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the front of the right cylinder head.
  14.  
  15. Position the exhaust manifold heat shield and bolts to the manifold and tighten to 80 inch lbs. (9 Nm).
  16.  
  17. Install the spark plugs.
    NOTE
    The manifold is removed below the vehicle.

  18.  
  19. Install the catalytic converter. Tighten the nuts to 37 ft. lbs. (50 Nm).
  20.  
  21. Lower the vehicle.
  22.  

 
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