Hummer H2. Manual - part 1883

1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488) or 

equivalent to the threads of the exhaust manifold bolts. Refer to Sealers, Adhesives, and Lubricants .  

2. Install the exhaust manifold and NEW exhaust manifold gasket. 

3. Install the exhaust manifold bolts. 

Tighten:  

1. Tighten the exhaust manifold bolts a first pass to 15 N.m (11 lb ft). Tighten the exhaust manifold 

bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside 
bolts.  

2. Tighten the exhaust manifold bolts a final pass to 25 N.m (18 lb ft). Tighten the exhaust manifold 

bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside 
bolts.  

4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left 

cylinder head. 

and free of debris or threadlocking material.  

IMPORTANT: Do not apply sealant to the first three threads of the bolt.

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

  

Fig. 683: Exhaust Manifold & Heat Shield 
Courtesy of GENERAL MOTORS CORP. 

5. Install the heat shield (603) and bolts (604). 

Tighten: Tighten the heat shield bolts to 9 N.m (80 lb in). 

EXHAUST MANIFOLD INSTALLATION - RIGHT 

 

2004 Hummer H2 

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

  

Fig. 684: Exhaust Manifold, Gasket & Bolt (Right) 
Courtesy of GENERAL MOTORS CORP. 

1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488) or 

equivalent to the threads of the exhaust manifold bolts. Refer to Sealers, Adhesives, and Lubricants .  

2. Install the exhaust manifold gasket and exhaust manifold. 

IMPORTANT:

z

Tighten the exhaust manifold bolts as specified in the service 
procedure. Improperly installed and/or leaking exhaust manifold 
gaskets may affect vehicle emissions and/or On-Board Diagnostic 
(OBD) II system performance.  

z

The cylinder head exhaust manifold bolt hole threads must be clean 
and free of debris or threadlocking material.  

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

  

3. Install the exhaust manifold bolts. 

Tighten:  

1. Tighten the exhaust manifold bolts first pass to 15 N.m (11 lb ft). Tighten the exhaust manifold 

bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside 
bolts.  

2. Tighten the exhaust manifold bolts final pass to 25 N.m (18 lb ft). Tighten the exhaust manifold 

bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside 
bolts.  

4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the front of the right 

cylinder head. 

Fig. 685: Manifold, Heat Shield & Bolts (Right) 
Courtesy of GENERAL MOTORS CORP. 

5. Install the heat shield (603) and bolts (604). 

Tighten: Tighten the heat shield bolts to 9 N.m (80 lb in).

 

2004 Hummer H2 

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