The exhaust system in either the L36 or L67 engine incorporates (in order from front to rear) an exhaust manifold front pipe, three way + oxidation catalytic converter, resonator, intermediate pipe, mufflers and tailpipes. The exhaust manifold front pipe is attached to the catalytic converter and is serviced separate of the catalytic converter. The exhaust crossover pipe attaches to the front and rear exhaust manifolds.
The exhaust system is supported at the rear of the resonator, and the rear of the muffler(s) by rubber isolated hangers to provide proper alignment.
Heat shields are attached to the underside of the body to reflect the heat of the exhaust system away from the body.
Caution: Always replace any heat shield that is removed. Failure to do so could cause damage to other components.
The front exhaust pipe attaches to the rear exhaust manifold. A joint coupling, using a round graphite impregnated seal, and flex coupling connects the rear exhaust manifold to the front exhaust pipe. The flex coupling allows angular movement between the engine and the exhaust system.
Notice: When a flex coupling is moved from the normal mounting position it is possible to over-flex and damage the flex coupling. Always support the flex coupling and pipe assembly in order to avoid over-flexing. The flex coupling is designed to flex a maximum of six degrees which is equivalent to the pipes connected to the joint moving no more than 1 inch for every 1 foot length of pipe. If the pipe connected to the joint is 3 feet long, the end of the pipe could be moved a maximum of 3 inches.
An exhaust system should never be suspended solely from the flex coupling.
Catalytic Converter
The catalytic converter is an emission control device. The catalytic converter is added to the exhaust system on unleaded fuel engine vehicles in order to reduce pollutants from the exhaust gas stream. The catalyst in the monolith converter is not servicable. The converter is the single bed type.
Notice: In order to avoid damage to the catalyst, use unleaded fuel only.
Heat Shields
The heat shields are attached to the vehicle underside of the body in order to reflect theheat of the exhaust system away from the body.
Caution: Always reinstall any heat shield that is removed. Failure to do so may cause damage to other components. The post catalytic converter oxygen sensor is protected by a heat shield, which is attached to the underside of the vehicle.
Exhuast System Hangers General Description
The exhaust system is supported by free-hanging rubber mountings. The rubber mountings serve the following functions:
| • | Permit exhaust system movement |
| • | Stop the transfer of noise into the passenger compartment |
| • | Stop the transfer of vibration into the passenger compartment |
The following conditions can cause exhaust system rattles and noise vibrations:
| • | Component misalignment |
| • | Heat shield retention |
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.
Leave all the bolts or the nuts loose until all the components are properly aligned. Tighten the bolts and the nuts from the front to the rear of the vehicle.
Exhaust system maintenance is not required. Inspect the condition of the catalytic converter, the pipes, and the mufflers if the vehicle is raised for other service.
