General Description
Notice: In order to prevent overheating of the floor panel or damage to the
passenger compartment, insulation, and trim materials, check the underbody
for adequate clearance when inspecting or replacing the exhaust system components.
The 3800 (VIN K) engine vehicles use the following components:
| • | A three-way catalytic converter with a single exhaust pipe |
| • | A single outlet exhaust muffler |
The 3800 (VIN K) engine vehicles with RPO Y87 (a performance enhancement
package) use the following components:
| • | A three-way catalytic converter with a single exhaust pipe |
The 5.7L (VIN P) engine vehicles use the following components:
| • | A dual three-way plus oxidation catalytic converter (oxidation
catalytic converter) |
| | with a single exhaust pipe |
Periodic maintenance of the exhaust system is not required. If the vehicle
is raised for other service, check the condition of the complete exhaust system.
Inspect the complete exhaust system, nearby body parts, and the rear
compartment lid for the following conditions:
| • | Broken or damaged parts |
| • | Mispositioned or missing parts |
| • | Other deterioration that could permit exhaust fumes to seep into
the rear compartment or the passenger compartment. |
Check the rear compartment for dust or water, which may indicate a problem
in this area.
Correct any faulty areas immediately.
Catalytic Converter
Caution: Prolonged operation of a misfiring or flooded engine may cause the catalytic
converter to overheat. Damage to the catalyst, the operating vehicle, or personal
injury may result.
Notice: When jacking or lifting the vehicle from the frame side rails, be certain
that the lift pads do not contact the catalytic converter. This may damage
the converter.
Notice: In order to avoid damage to the catalyst, use unleaded fuel only.
The catalytic converter is an emission control device added
to the exhaust system in order to reduce pollutants from the exhaust gas stream.
The three-way catalytic converter burns three types of exhaust gases:
| • | Oxides of nitrogen (NOx) |
The oxidation catalytic converter burns the same gases, but uses an
air pump/smog pump to force added oxygen into the catalytic converter. The
additional oxygen forces the converter to run hotter and to burn exhaust gases
more effectively.
A single bed ceramic monolith style brick catalytic converter is used
in combination with two types of catalyst
| • | Three-way (reduction/oxidation) catalyst |
The catalysts have coatings that contain platinum and palladium. These
coatings burn the unwanted exhaust emissions.
Exhaust Muffler
The exhaust muffler is a tri-flow design.
The muffler has a slot in the inlet pipe. The slot indexes to a key
(tab) welded on the exhaust pipe in order to help maintain alignment.
On the 3800 (VIN K) engine, there are two exhaust muffler designs.
| • | Engines without RPOs Y87 and W68 use a single outlet muffler. |
| • | Engines with RPO Y87 use a dual outlet muffler. |
The 5.7L (VIN P) engine uses the dual outlet muffler.
Hangers
Important: The installation of exhaust system hangers is very important, as improperly
installed hangers can cause annoying vibrations that can be difficult to diagnose.
Two types of hangers support the exhaust system. One is a conventional
rubber strap. The other is a rubber block. The rubber block type is a rigid
hanger with a feature that supports the exhaust system when a rubber insulator
block is broken.
Clamps and Welded Connections
Caution: Exhaust may enter the vehicle and cause personal injury if the slip
joints are not coated with exhaust system sealer before assembly.
Clamps and welds
connect the exhaust system slip joints. When installing replacement parts,
cut the welded connection and clamp the new connection.
Three types of clamps connect the exhaust system slip joints:
On-Vehicle Service and Component Replacement
Exhaust system service includes the replacement of the following items:
| • | The catalytic converter |
| • | The catalytic converter and the exhaust muffler hangers |
| • | The complete exhaust system |
| • | The exhaust heat shield |
| • | The exhaust muffler with tail pipe(s) |
Exhaust System Clearance Dimensions
Make all checking dimensions on a cold exhaust system.
If the specified dimensions cannot be met, there is a quality deficiency
in a component. Correct the deficiency.
