Description and operation

Exhaust system

DESCRIPTION

CAUTION: Avoid application of rust prevention compounds or undercoating materials to exhaust system floor pan exhaust heat shields. Light overspray near the edges is permitted. Application of coating will result in excessive floor pan temperatures and objectionable fumes.

The gasoline engine exhaust system consists of engine exhaust manifolds, exhaust pipes, catalytic converter(s), extension pipe (if needed), exhaust heat shields, muffler and exhaust tailpipe (Fig. 1).

The exhaust system must be properly aligned to prevent stress, leakage and body contact. Minimum clearance between any exhaust component and the body or frame is 25.4 mm (1.0 in.). If the system contacts any body panel, it may amplify objectionable noises from the engine or body.

OPERATION

The exhaust system channels exhaust gases from the engine and away from the vehicle.

Fig. 1 Exhaust System 4.7L, 5.2L and 5.9L Engines-Typical

1 - TAILPIPE

2 - MUFFLER HANGER BRACKET AND ISOLATOR

3 - CLAMP

4 - EXHAUST PIPE

5 - CATALYTIC CONVERTER

6 - EXTENSION PIPE

7 - MUFFLER HEAT SHIELD

Catalytic converter

DESCRIPTION

California emissions vehicles incorporate mini catalytic converters into the exhaust system. The pipes and catalytic converters are made of stainless steel designed to operate at extremely high temperatures (Fig. 2).

Fig. 2 Catalytic Converter-Typical

1 - EXHAUST PIPE

2 - CONVERTER

3 - MUFFLER

4 - CLAMP

OPERATION

The catalytic converter captures and burns any unburned fuel mixture exiting the combustion chambers during the exhaust stroke of the engine. This process aids in reducing emissions output.

Exhaust pipe

DESCRIPTION

The exhaust pipe(s) is a one piece design encompassing the exhaust pipe(s) and the catalytic converter( s). Neither the exhaust pipe(s) or the catalytic converter(s) is serviceable separately (Fig. 3).

Muffler

DESCRIPTION

All engines use a stainless steel muffler to control exhaust noise levels and exhaust back pressure (Fig.

4).

Fig. 3 Exhaust Pipe with Integral Catalytic Converter(s)

1 - NUT

2 - EXHAUST PIPE

3 - MINI CATALYTIC CONVERTERS (CALIFORNIA EMISSIONS VEHICLES ONLY)

4 - CATALYTIC CONVERTER

Fig. 4 Muffler-Typical

1 - CATALYTIC CONVERTER WITH PIPE

2 - REAR MUFFLER HANGER

3 - MUFFLER

4 - CLAMP

OPERATION

The muffler is designed to muffle the sound of the exhaust as if leaves the engine.

Tailpipe

DESCRIPTION

The tailpipe is made of stainless steel and attaches to the muffler (Fig. 5).

Fig. 5 Tailpipe-Typical

1 - MUFFLER

2 - TAILPIPE HANGER INSULATOR

3 - TAILPIPE HANGER

4 - TAILPIPE

5 - CLAMP

OPERATION

The tailpipe channels the exhaust out of the muffler and out from under the vehicle to control noise and prevent exhaust gas fumes from entering the passenger compartment.

Heat shields

DESCRIPTION

There are two types of heat shields used. One is stamped steel the other is molded foil sheets. The shields attach to the vehicle around the exhaust system (Fig. 6).

OPERATION

The heat shields prevent heat from the exhaust system from entering the passenger area and other areas where the heat can cause damage to other components.

Fig. 6 Heat Shield-Typical

1 - MUFFLER HEAT SHIELD

2 - MUFFLER HANGERS