Hummer H2. Manual - part 1894

EXHAUST NOISE 

Exhaust Noise 

REPAIR INSTRUCTIONS 

EXHAUST MANIFOLD REPLACEMENT - LEFT 

Removal Procedure 

Irregularities at the mating surfaces on 
the flange connections.

Repair as required or replace the affected component. Refer to 
the affected components procedure for service.

Exhaust manifold cracked or broken.

Replace the exhaust manifold. Refer to 

z

Exhaust Manifold Replacement - Left  

z

Exhaust Manifold Replacement - Right .  

Exhaust system component connection 
welds leaking.

Replace the leaking component. Refer to the affected 
component's procedure for service.

Muffler damaged or leaking at the 
seams.

Replace the affected muffler. Refer to Muffler Replacement .

Condition

Action

DEFINITION: An audible or physical noise due to a faulty component or damaged components causing 
a loose or misaligned exhaust system resulting in a rattle or vibration noise (buzz, groan, hum).Refer to 
Symptoms - Engine Exhaust prior to beginning this table.

CAUTION:

While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid 
contacting a hot exhaust system.

Popping or hissing noise

Exhaust leak. Refer to Exhaust Leakage .

Loud exhaust

1. Compare to a known good vehicle.  

2. Inspect for a damaged or failed muffler or resonator.  

3. Replace the faulty muffler. Refer to Muffler Replacement .  

External rattle or vibration 
noise

1. Inspect for a bent or loose hanger, loose heat shield, or loose clamp.  

2. Inspect for a exhaust pipe causing interference.  

3. Repair or replace the affected component. Refer to the affected 

component's service procedure.  

Internal rattle

1. Test the components by tapping with a rubber mallet to confirm a 

rattle.  

2. Replace the faulty catalytic converter, or muffler. Refer to one of the 

following procedures: 

z

Catalytic Converter Replacement (Right Hand)  

z

Muffler Replacement  

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2

  

Fig. 1: Exhaust Manifold Pipe Nuts (Left) 
Courtesy of GENERAL MOTORS CORP. 

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. 

2. Remove the exhaust manifold pipe nuts.  

3. Lower the vehicle.  

4. Remove the spark plug wires. Refer to Spark Plug Wire Replacement in Engine Controls - 4.8L, 5.3L 

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2

  

and 6.0L. 

Fig. 2: Exhaust Manifold Bolts, Manifold & Gasket 
Courtesy of GENERAL MOTORS CORP. 

5. Remove the exhaust manifold bolts, manifold, and gasket.  

6. Discard the gasket. 

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2

  

Fig. 3: View Of Heat Shield & Bolts 
Courtesy of GENERAL MOTORS CORP. 

7. Remove the heat shield bolts (3), and shield (2) from the exhaust manifold (1), if necessary.  

8. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold 

Cleaning and Inspection in the Engine Mechanical - 4.8L, 5.3L and 6.0L.  

Installation Procedure 

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2