Hummer H3. Manual — part 406

installed piston pin retainer.

Fig. 455: View Of Piston Pin Retaining Clips
Courtesy of GENERAL MOTORS CORP.

4. Install the second piston pin retainer.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Fig. 456: Piston Ring Expander
Courtesy of GENERAL MOTORS CORP.

5. Install the following components of the bottom ring assembly (oil control ring).

NOTE:

Use a piston ring expander to install the piston rings. The rings
may be damaged if expanded more than necessary.

IMPORTANT: The piston ring end gaps must be staggered 90 degrees

apart.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

1. The expander

2. The lower oil control ring

3. The upper oil control ring

Fig. 457: Identifying Middle Ring

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Courtesy of GENERAL MOTORS CORP.

6. Install the middle ring (compression ring) with the napier groove facing down.

7. Install the top ring.

CAMSHAFTS CLEANING AND INSPECTION

Tools Required

J 7872 Magnetic Base Dial Indicator Set

Cleaning and Inspection Procedure

Fig. 458: Measuring Camshaft Lobes
Courtesy of GENERAL MOTORS CORP.

1. Clean the camshafts with cleaning solvent.

2. Inspect the camshafts for the following conditions:

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3