Hummer H2. Manual — part 1830

1. Clean the cylinder head valve spring shim area.

2. Install the valves (227 and 228) into the proper port.

Refer to Separating Parts .

3. Install the valve stem oil seal (222).

4. Install the valve spring (223).

5. Install the valve spring cap (224).

IMPORTANT: When using the valves and related components again, install the parts to

their original location.

IMPORTANT: The valve stem oil seal alignment and position on the valve guide is

critical.
An improperly installed valve stem oil seal may lead to excessive oil
consumption, increased vehicle emissions, or component damage.

2004 Hummer H2

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

Fig. 491: Compressing Valve Spring Using J 8062
Courtesy of GENERAL MOTORS CORP.

6. Compress the valve spring using the J 8062 . See Special Tools and Equipment .

7. Install the valve stem keys.

1. Use grease to hold the keys in place and remove the J 8062 . See Special Tools and Equipment .

2. Ensure the keys seat properly in the groove of the valve stem.

2004 Hummer H2

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

3. Tap the end to the valve stem with a plastic faced hammer to seat the keys, if necessary.

Fig. 492: Measuring Valve Spring Installed Height
Courtesy of GENERAL MOTORS CORP.

8. Measure the valve spring installed height using a ruler.

Measure from the base of the valve spring to the top of the valve spring.

Specification:

z

If the installed height exceeds 46.25 mm (1.82 in), install a valve spring shim of approximately 0.5
mm (0.02 in) thick.

z

Do not shim the valve spring to obtain less than the specified height.

2004 Hummer H2

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

Do not assemble the components without a spring shim on the cylinder head.

9. Install the remaining valves, springs, and other components.

Fig. 493: Coolant Temperature Sensor (Left Cylinder Head)
Courtesy of GENERAL MOTORS CORP.

10. Install sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the coolant

sensor.

11. Install the coolant temperature sensor into the left cylinder head.

Tighten: Tighten the coolant temperature sensor to 20 N.m (15 lb ft).

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