Exhaust System: Description and Operation

Exhaust System

Exhaust System
The exhaust system provides an exit for exhaust gases and reduces engine noise by passing exhaust gases through the catalytic converter and a 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.

The catalytic converter is designed to provide a 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, a new sound insulator and shield should be installed. The sound insulators and shields for the muffler, exhaust downpipe, inlet pipe and catalytic converter pipe are installed separately.

Precautions

WARNING: The normal operating temperature of the exhaust system is very high. Never work around or attempt to repair any part of the exhaust system until it has cooled. Use special care when working around the catalytic converter. The catalytic converter heats to a high temperature after only a short period of engine operation. Failure to follow these instructions may result in personal injury.

WARNING: Exhaust gases contain carbon monoxide which can be harmful to health and are potentially lethal. Exhaust system leaks should be repaired immediately. Never operate the engine in enclosed areas. Failure to follow these instructions may result in personal injury.

CAUTION: Do not use leaded fuel in a vehicle equipped with catalytic converter.

CAUTION: 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 can destroy the catalyst and render the catalytic converter useless.

CAUTION: The addition of lead to the catalytic converter can also solidify the catalyst, causing excessive back pressure in the exhaust system and possibly causing engine damage.

CAUTION: Extremely high temperatures of 1,100°C (2,012°F) or above due to misfiring or 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.

CAUTION: Do not use oil or grease-based lubricants on the isolators. These lubricants may cause deterioration of the rubber. This can lead to separation of the isolator from the exhaust hanger bracket during vehicle operation. Use only water-based lubricants on the isolators.

NOTE: Exhaust fasteners are of a prevailing torque design. Use only new fasteners with the same part number as the original. Torque values must be used as specified during reassembly to make sure of correct retention of exhaust components.

NOTE: Always install new gasket, fasteners, clamp and service coupler (if equipped) whenever an exhaust joint is loosened.

Apply anti-seize lubricant to the threads of the heated oxygen sensors (HO2S) and catalyst monitor sensor before installation.