Hummer H2. Manual - part 1829

4. Reface pitted exhaust valves on a suitable valve refacing machine.  

5. Replace the valve if the margin is less than 1.25 mm (0.05 in) thick after grinding.  

6. If the valve face has been ground, it may be necessary to shim the valve spring to obtain the proper spring 

installed height. Refer to Cylinder Head Disassemble . 

 

2004 Hummer H2 

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

  

Fig. 489: Cylinder Head Components 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

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

  

7. Inspect for a loose valve seat in the cylinder head (218). The valve seat has an interference fit to the 

cylinder head.  

8. Clean the valve guide bores with a suitable tool. Remove all carbon or dirt from the bores. 

The valve guide must be clean for the seat grinding tool to obtain proper results. 

9. Grind the valve seat. 

The recommendations of the manufacturer of the equipment should be followed carefully to obtain the 
proper results. Regardless of what type of equipment is used, it is essential that valve guide bores be free 
from carbon or dirt to ensure proper centering of the tool pilot in the guide. 

10. Inspect the valve seats. 

z

The valve seats should be concentric to within 0.05 mm (0.0021 in) total indicator reading.  

z

If the valve seat has been ground, it may be necessary to shim the valve spring to attain the proper 
spring installed height. 

Refer to Cylinder Head Disassemble . 

CYLINDER HEAD ASSEMBLE 

Tools Required 

J 8062 Valve Spring Compressor - Head Off. See Special Tools and Equipment . 

 

2004 Hummer H2 

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

  

Fig. 490: Cylinder Head Components 
Courtesy of GENERAL MOTORS CORP.

 

2004 Hummer H2 

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