H3 2006

Exhaust System

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Catalytic Converter



Removal & Installation
3.5L & 3.7L Engines

CAUTION
In order to avoid being burned, do not service the exhaust system while it is still hot. Service the system when it is cool.


CAUTION
Always wear protective goggles and gloves when removing exhaust parts as falling rust and sharp edges from worn exhaust components could result in serious personal injury.

  1. Remove the right torsion bar.
  2.  
  3. Disconnect the Heated Oxygen Sensor (HO2S) at the sensor pigtail.
  4.  
  5. Remove the HO2S if replacement is necessary.
    CAUTION
    Do not use oil base lubricants.

  6.  
  7. Apply a soapy solution to the exhaust muffler hanger rod in order to ease the removal of the exhaust hanger, if necessary.

    Click image to see an enlarged view

    Fig. Apply a soapy solution to the exhaust muffler hanger rod (3) in order to ease the removal of the exhaust hanger (2), if necessary

  8.  
  9. Pry the exhaust hanger free from the exhaust muffler hanger rod, if necessary.
  10.  
  11. Remove the nuts securing the muffler to the catalytic converter.

    Click image to see an enlarged view

    Fig. Remove the nuts securing the muffler to the catalytic converter

  12.  
  13. Position the muffler rearward enough to allow the studs located in the muffler to clear the catalytic converter pipe flange.
  14.  
  15. Remove the nuts attaching the catalytic converter to the exhaust manifold.

    Click image to see an enlarged view

    Fig. Remove the nuts attaching the catalytic converter to the exhaust manifold

  16.  
  17. Remove the catalytic converter.
  18.  
  19. Remove and discard the exhaust manifold seal at the exhaust manifold flange.
  20.  

To install:

  1. Install a NEW seal to the exhaust manifold flange.
  2.  
  3. Install the catalytic converter to the exhaust manifold.
  4.  
  5. Install the nuts attaching the catalytic converter to the exhaust manifold. Do not tighten at this time.
  6.  
  7. Align the catalytic converter with the studs located in the muffler.
  8.  
  9. Install the nuts securing the muffler to the catalytic converter. Tighten the nuts by hand until each contacts the metal flange. Tighten the nuts to 33 ft. lbs. (45 Nm).
  10.  
  11. Tighten the catalytic converter nuts previously installed in step 3. Tighten the nuts to 37 ft. lbs. (50 Nm).
  12.  
  13. Install the HO2S if previously removed.
    CAUTION
    Do not use oil base lubricants.

  14.  
  15. Apply a soapy solution to the following in order to ease the installation of the hanger:

    The inner diameter of the exhaust muffler hanger
     
    The exhaust muffler hanger rod
     

  16.  
  17. Connect the HO2S at the pigtail.
  18.  
  19. Install the right torsion bar.
  20.  

5.3L Engine
Left Side

Specific to:

Hummer H3 2006-2010

  1. Remove catalytic convertor guard.
  2.  
  3. Remove the heated oxygen sensors (HO2S).
  4.  
  5. Remove the catalytic converter to muffler nuts.

    Click image to see an enlarged view

    Fig. Remove the catalytic converter to muffler nuts (1); loosen the muffler to catalytic converter clamp (2)

  6.  
  7. Loosen the muffler to catalytic converter clamp.
  8.  
  9. With the aid of an assistant, separate the muffler hangers from the insulators.

    Click image to see an enlarged view

    Fig. Separate the muffler hangers from the insulators (1); muffler (2)

  10.  
  11. Separate the muffler from the catalytic converters.
  12.  
  13. Reposition the muffler rearward as far as possible, and support using the rear axle and jack stands.
  14.  
  15. Remove the catalytic converter to exhaust manifold nuts.

    Click image to see an enlarged view

    Fig. Remove the catalytic converter to exhaust manifold nuts (2), the catalytic converter (1) and seal (3)

  16.  
  17. Remove the catalytic converter and seal.
  18.  

To install:

  1. Install the catalytic converter and seal.
  2.  
  3. Install the catalytic converter to exhaust manifold nuts. Tighten the nuts to 37 ft. lbs. (50 Nm).
  4.  
  5. With the aid of an assistant, remove the muffler from the jack stands.
  6.  
  7. Install the muffler to the catalytic converters.
  8.  
  9. Install the muffler hangers to the insulators.
  10.  
  11. Install the catalytic converter to muffler nuts. Tighten the nuts to 33 ft. lbs. (45 Nm).
  12.  
  13. Tighten the muffler to catalytic converter clamp. Tighten the clamp to 32 ft. lbs. (43 Nm).
  14.  
  15. Install the HO2S.
  16.  
  17. Install catalytic convertor guard.
  18.  
  19. Inspect exhaust system for leaks.
  20.  

Right Side

Specific to:

Hummer H3 2006-2010

  1. Remove the right torsion bar.
  2.  
  3. Remove the heated oxygen sensors (HO2S).
  4.  
  5. Remove the transmission support crossmember.
  6.  
  7. Remove the catalytic converter to muffler nuts.

    Click image to see an enlarged view

    Fig. Remove the catalytic converter to muffler nuts (1); loosen the muffler to catalytic converter clamp (2)

  8.  
  9. Loosen the muffler to catalytic converter clamp.
  10.  
  11. With the aid of an assistant, separate the muffler hangers from the insulators.

    Click image to see an enlarged view

    Fig. Separate the muffler hangers from the insulators (1); muffler (2)

  12.  
  13. Separate the muffler from the catalytic converters.
  14.  
  15. Reposition the muffler rearward as far as possible, and support using the rear axle and jack stands.
  16.  
  17. Remove front propeller shaft.
  18.  
  19. Remove the catalytic converter to exhaust manifold nuts.

    Click image to see an enlarged view

    Fig. Remove the catalytic converter to exhaust manifold nuts (2), the catalytic converter (3) and seal (1)

  20.  
  21. With the aid of an assistant, remove the catalytic converter and seal.
  22.  

To install:

  1. With the aid of an assistant, install the catalytic converter and seal.
  2.  
  3. Install front propeller shaft.
    NOTE
    Ensure at least 7 mm of clearance between the bell housing and the catalytic convertor. Use an assistant to hold and rotate the pipe counterclockwise while tightening the nuts.

  4.  
  5. Install the catalytic converter to exhaust manifold nuts. Tighten the nuts to 37 ft. lbs. (50 Nm).
  6.  
  7. With the aid of an assistant, remove the muffler from the jack stands.
  8.  
  9. Install the muffler to the catalytic converters.
  10.  
  11. Install the muffler hangers to the insulators.
  12.  
  13. Install the catalytic converter to muffler nuts. Tighten the nuts to 33 ft. lbs. (45 Nm).
  14.  
  15. Tighten the muffler to catalytic converter clamp. Tighten the clamp to 32 ft. lbs. (43 Nm).
  16.  
  17. Install the transmission support crossmember.
  18.  
  19. Install the HO2S.
  20.  
  21. Install the right torsion bar.
  22.  

 
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