Hummer H2. Manual - part 1826

Fig. 479: Inspecting Valve Spring For Squareness 
Courtesy of GENERAL MOTORS CORP. 

4. Inspect the valve springs for squareness. 

 

2004 Hummer H2 

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

  

Fig. 480: Measuring The Valve Spring Using J 9666 
Courtesy of GENERAL MOTORS CORP. 

5. Use the J 9666 in order to measure the valve spring tension. 

Replace the spring if the spring tension is less than 310 N (70 lb) at 45.75 mm (1.80 in). 

VALVE GUIDE REAMING/VALVE AND SEAT GRINDING 

Tools Required 

 

2004 Hummer H2 

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

  

J 37378-1 Valve Guide Reamer. See Special Tools and Equipment .

Valve Guide Reaming 

Fig. 481: Measuring Valve Stem-To-Guide Clearance 
Courtesy of GENERAL MOTORS CORP. 

 

2004 Hummer H2 

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

  

1. Measure the valve stem-to-guide clearance using a dial indicator. Position the tip of the dial indicator at 

the top of the valve guide. 

Valve stem-to-guide clearance may also be obtained by using a micrometer to measure the valve stem 
diameter and a ball type measuring gauge to measure the guide bore.

IMPORTANT:

z

Excessive valve stem-to-guide clearance may cause a noisy valve 
train, premature valve stem oil seal wear, component damage, and/or 
excessive engine oil consumption.  

z

Insufficient valve stem-to-guide clearance will result in noisy or 
sticking valves. Valves that are too tight may disturb engine 
smoothness or lead to component damage.  

 

2004 Hummer H2 

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