Hummer H2. Manual - part 1825

Fig. 476: Cleaning Carbon Using J 8089 
Courtesy of GENERAL MOTORS CORP. 

1. Clean the following components: 

IMPORTANT: When cleaning a cylinder head in a thermal type oven, do not exceed 204°

C (400°F).

CAUTION: Refer to Safety Glasses Caution in Cautions and Notices.

IMPORTANT: Be careful not to scuff the chamber.

 

2004 Hummer H2 

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

  

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Use the J 8089 in order to remove the carbon from the combustion chambers.  

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Gasket surfaces 

Refer to Replacing Engine Gaskets . 

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Valve stems and heads on a buffing wheel  

z

Bolt hole threads 

Remove all dirt, debris, or threadlocking material from the bolt holes. 

 

2004 Hummer H2 

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

  

Fig. 477: Cylinder Head Components 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

  

2. Inspect the following components: 

1. The cylinder head (218) for cracks in the exhaust ports and combustion chambers  

2. The cylinder head for external cracks in the water chambers  

3. The gasket surfaces for excessive scratches or gouging 

Refer to Replacing Engine Gaskets . 

4. The bolt hole threads for debris or damaged threads 

Refer to Thread Repair or Thread Repair Specifications . 

Fig. 478: Measuring Cylinder Head For Warpage 
Courtesy of GENERAL MOTORS CORP. 

3. Inspect the cylinder head for warpage. Refer to Engine Mechanical Specifications . 

 

2004 Hummer H2 

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2