Exhaust System: Description and Operation

Exhaust System

The 3.7L exhaust system consists of:

- two exhaust manifold mounted catalytic converters.
- an exhaust Y-pipe.
- a muffler and tail pipe assembly.
- isolators installed on the body and muffler hangers.

The 3.5L Gasoline Turbocharged Direct Injection (GTDI) exhaust system consists of:

- two turbocharger mounted catalytic converters.
- two flexible pipe assemblies.
- an underbody catalytic converter.
- a muffler and tail pipe assembly.
- isolators installed on the body and muffler hangers.

The exhaust system provides an exit for exhaust gases and reduces engine noise by passing exhaust gases through the catalytic converters and muffler assembly. Rubber exhaust hanger isolators attach the exhaust system to the mounting hooks.


Catalytic Converter

The catalytic converter plays a major role in the emission control system. The catalytic converter operates as a gas reactor. Its catalytic function is to speed the heat-producing chemical reaction of components in the exhaust gases in order to reduce air pollutants.

The catalyst material inside the catalytic converter consists of a ceramic substrate.

Precautions

NOTICE: Do not use leaded fuel in a vehicle equipped with a catalytic converter. In a vehicle that is continually misfueled, the lead in the fuel will be deposited in the catalytic converter and completely blanket the catalyst. Lead reacts with platinum to "poison" the catalyst. Continuous use of leaded fuel may destroy the catalyst and render the catalytic converter useless. The addition of lead to the catalytic converter may also solidify the catalyst, causing excessive back pressure in the exhaust system and possibly causing engine damage.

NOTICE: Extremely high temperatures of 1,100°C (2,012°F) or above due to misfiring or an over-rich fuel/air mixture will cause the ceramic substrate to sinter or burn, destroying the catalytic converter. Do not continue to operate the vehicle if the engine is misfiring, there is a power loss, or other unusual operating conditions, such as engine overheating and backfiring.

The catalytic converter is designed to provide long life. No maintenance is necessary for the catalytic converter.


Sound Insulators and Shields

Sound insulators and shields, attached to the underbody, protect the vehicle from exhaust system heat and should be inspected at regular intervals to make sure they are not dented or out of position. If a sound insulator and shield is damaged or shows evidence of deterioration, it should be replaced. The sound insulators and shields for the muffler, muffler pipe, resonator and catalytic converter pipe are installed separately.