Hummer H3. Manual — part 1171

Fig. 38: View Of Exhaust Pipe Heat Shield At Floor Panel
Courtesy of GENERAL MOTORS CORP.

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

2. Remove the nuts securing the heat shield to the floor panel.

3. Remove the exhaust pipe heat shield.

Installation Procedure

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3

Fig. 39: View Of Exhaust Pipe Heat Shield At Floor Panel
Courtesy of GENERAL MOTORS CORP.

1. Position the exhaust pipe heat shield to the floor panel studs.

2. Install the nuts securing the heat shield to the floor panel.

Tighten: Tighten the nuts to 9 N.m (80 lb in).

3. Lower the vehicle.

DESCRIPTION AND OPERATION

EXHAUST SYSTEM DESCRIPTION

The exhaust system carries exhaust gases, treated by the catalytic converter, through a resonator,
if applicable and into the exhaust muffler where exhaust noise is lessened.

In order to secure the exhaust pipe to the exhaust manifold, a flange and seal-joint coupling is
utilized. The exhaust system may utilize a slip-joint coupling design with a clamp and a U-bolt or
a flange connection with a gasket.

Exhaust hangers and rubber insulators help to support the weight of the exhaust pipe along with
insulating any exhaust system vibration, rattle or noise.

Exhaust hangers also space the exhaust system away from the underbody of the vehicle and allows
the exhaust system to expand as the exhaust system warms up.

Exhaust heat shields are used to protect the body and other components from damage due to the
heat from the exhaust system.

The exhaust system may be comprised of the following components:

Exhaust manifold

Exhaust pipes

Catalytic converters

NOTE:

Refer to Fastener Notice .

IMPORTANT: Use of non-OEM parts may cause driveability concerns.

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3

Exhaust muffler

Exhaust resonator, if equipped

Exhaust tail pipe, if equipped

Exhaust hangers

Exhaust heat shields

Resonator

Some exhaust systems are equipped with a resonator. The resonator, located either before or after
the muffler, allows the use of mufflers with less back pressure. Resonators are used when vehicle
characteristics require specific exhaust tuning.

Catalytic Converter

The catalytic converter is an emission control device added to the engine exhaust system in order
to reduce hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx) pollutants
from the exhaust gas.

The catalytic converter is comprised of a ceramic monolith substrate, supported in insulation and
housed within a sheet metal shell. The substrate may be washcoated with 3 noble metals:

Platinum (Pt)

Palladium (Pd)

Rhodium (Rh)

The catalyst in the converter is not serviceable.

Muffler

The exhaust muffler reduces the noise levels of the engine exhaust by the use of tuning tubes. The
tuning tubes create channels inside the exhaust muffler that lower the sound levels created by the
combustion of the engine.

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

Special Tools

Illustration

Tool Number/Description

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3