Hummer H2. Manual - part 1724

Fig. 99: Valve Rocker Arms 
Courtesy of GENERAL MOTORS CORP. 

5. Install the rocker arms and bolts. 

IMPORTANT: Make sure that the pushrods seat properly to the ends of the rocker arms. 

DO NOT tighten the rocker arm bolts at this time.

 

2004 Hummer H2 

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

  

Fig. 100: View Of Crankshaft 
Courtesy of GENERAL MOTORS CORP. 

NOTE:

Refer to Fastener Notice in Cautions and Notices.

 

2004 Hummer H2 

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

  

6. Rotate the crankshaft until the number one piston is at top dead center (TDC) of the compression stroke. 

In this position, cylinder number one rocker arms will be off lobe lift, and the crankshaft sprocket key 
will be at the 1:30 position. 

The engine firing order is 1,8,7,2,6,5,4,3. 

Cylinders 1,3,5 and 7 are the left bank. 

Cylinder 2,4,6 and 8 are the right bank. 

7. With the engine in the number one firing position, tighten the following valve rocker arm bolts: 

Tighten:  

z

Tighten the cylinders 1,2,7 and 8 exhaust valve rocker arm bolts to 30 N.m (22 lb ft).  

z

Tighten the cylinders 1,3,4 and 5 intake valve rocker arm bolts to 30 N.m (22 lb ft).  

8. Rotate the crankshaft 360 degrees.  

9. Tighten the following valve rocker arm bolts: 

Tighten:  

z

Tighten the cylinders 3, 4, 5 and 6 exhaust valve rocker arm bolts to 30 N.m (22 lb ft).  

z

Tighten the cylinders 2, 6, 7 and 8 intake valve rocker arm bolts to 30 N.m (22 lb ft).  

10. Install the valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement - Left or Valve 

Rocker Arm Cover Replacement - Right .  

VALVE STEM OIL SEAL AND VALVE SPRING REPLACEMENT 

Tools Required 

z

J 22794 Spark Plug Port Adapter. See Special Tools and Equipment .  

z

J 38606 Valve Spring Compressor. See Special Tools and Equipment .  

Removal Procedure 

 

2004 Hummer H2 

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

  

Fig. 101: Spark Plug Wire & Boot 
Courtesy of GENERAL MOTORS CORP. 

1. Remove the valve rocker arm. Refer to Valve Rocker Arm and Push Rod Replacement .  

2. Disconnect the spark plug wire at the spark plug. 

z

Twist each plug wire boot 1/2 turn.  

z

Pull only on the boot in order to remove the wire from the spark plug.  

 

2004 Hummer H2 

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