GM: Electra/Park Avenue/Ninety-Eight 1990-1993



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Fig. Fig. 1 Exhaust pipe-to-manifold connection

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Fig. Fig. 2 Intermediate pipe hanger

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Fig. Fig. 3 Muffler hanger

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Fig. Fig. 4 Intermediate pipe installation

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Fig. Fig. 5 Exhaust system heat shield positioning

Catalytic converters under some conditions can reach temperatures well above 1000°F. They can become very hot very fast when the engine is running. They also stay hot for a long period of time after the engine has been turned off.

Most factory-new exhaust is a one-piece welded system. This means that even though you can purchase just one piece of the system from an aftermarket supplier you may not be able to install it with out cutting and welding. Once the original system has been replaced, then most parts are serviceable separately.

It is advisable before purchasing any parts to examine the system completely to how much of the system must be serviced. Look for components that are bolted at each end, in order to know that piece is replaceable. Some welded parts can be cut and new ones bolted or clamped on, but the parts supplier you deal with should be able to tell you if the parts he sells would fit or if you may need to replace other connected components.

Most of the bolts on the exhaust system will break when you try to loosen them. Be prepared; many times an exhaust manifold has to be removed due the broken exhaust stud that holds on the pipe. These bolts and studs become brittle due to the extreme heat and temperature changes. The procedures covered in this section are for replaceable (non-welded) components.

Whenever working on the exhaust system please observe the following:

  1. Check the complete exhaust system for open seams, holes loose connections, or other deterioration which could permit exhaust fumes to seep into the passenger compartment.
  3. The exhaust system is supported by free-hanging rubber mountings which permit some movement of the exhaust system, but do not permit transfer of noise and vibration into the passenger compartment.
  5. Before removing any component of the exhaust system, always squirt a liquid rust dissolving agent onto the fasteners for ease of removal.
  7. Annoying rattles and noise vibrations in the exhaust system are usually caused by misalignment of the parts. When aligning the system, leave all bolts and nuts loose until all parts are properly aligned, then tighten, working from front to rear.
  9. When replacing a muffler and/or resonator, the tailpipe(s) should also be replaced.
  11. When installing exhaust system parts, make sure there is enough clearance between the hot exhaust parts, and pipes and hoses that would be adversely affected by excessive heat. Also make sure there is adequate clearance from the floor pan to avoid possible overheating of the floor.
  13. Exhaust pipe sealers should be used at all slip joint connections except at the catalytic convertor. Do not use any sealers at the convertor as the sealer will not withstand convertor temperatures.