Hummer H2. Manual - part 1898

12. Lower the vehicle.  

13. Fill the cooling system. Refer to Draining and Filling Cooling System in Engine Cooling.  

EXHAUST MANIFOLD PIPE REPLACEMENT 

Removal Procedure 

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

2. Remove the engine protection shield. Refer to Engine Protection Shield Replacement in Frame and 

Underbody. 

Fig. 13: View Of O2 Sensor Harness 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2

  

3. Remove the exhaust muffler. Refer to Muffler Replacement .  

4. Remove the clip around the engine harness and the oxygen sensor pigtail.  

5. Disconnect the connector position assurance (CPA) retainer.  

6. Disconnect the oxygen sensor electrical connector.  

7. If replacing the exhaust manifold pipe, remove the oxygen sensor. 

Fig. 14: Exhaust Manifold Pipe Nuts (Right) 
Courtesy of GENERAL MOTORS CORP. 

8. Remove the exhaust manifold pipe nuts. 

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2

  

Fig. 15: Exhaust Manifold Pipe 
Courtesy of GENERAL MOTORS CORP. 

9. Remove the exhaust manifold pipe.  

10. Slide the exhaust manifold pipe hanger out of the exhaust pipe hanger bracket.  

11. Discard the exhaust manifold pipe seal.  

Installation Procedure 

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2

  

Fig. 16: Exhaust Manifold Pipe 
Courtesy of GENERAL MOTORS CORP. 

1. Install a new exhaust manifold pipe seal to the exhaust manifold pipe.  

2. Install the exhaust manifold pipe.  

3. Apply lubricant to the exhaust pipe hanger bracket, in order to aid in installation.  

4. Slide the exhaust manifold pipe hanger into the exhaust pipe hanger bracket. 

 

2004 Hummer H2 

2004 ENGINE Engine Exhaust - Hummer H2