GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Safety Precautions


See Figure 1

Safety glasses should be worn at all times when working on or near the exhaust system. Older exhaust systems will almost always be covered with loose rust particles which will shower you when disturbed. These particles are more than a nuisance and could injure your eye.

Whenever working on the exhaust system always follow these safety precautions:

  1. Support the truck extra securely. Not only will you often be working directly under it, but you'll frequently be using a lot of force, say, heavy hammer blows, to dislodge rusted parts. This can cause a truck that's improperly supported to shift and possibly fall.
  3. Wear goggles. Exhaust system parts are always rusty. Metal chips can be dislodged, even when you're only turning rusted bolts. Attempting to pry pipes apart with a chisel makes the chips fly even more frequently.
  5. If you're using a cutting torch, keep it a great distance from either the fuel tank or lines. Stop what you're doing and feel the temperature of the fuel bearing pipes on the tank frequently. Even slight heat can expand and/or vaporize fuel, resulting in accumulated vapor, or even a liquid leak, near your torch.
  7. Watch where your hammer blows fall and make sure you hit squarely. You could easily tap a brake or fuel line when you hit an exhaust system part with a glancing blow. Inspect all lines and hoses in the area where you've been working.
  9. 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.
  11. The exhaust system is supported by free-hanging rubber mountings which permit some movement of the exhaust components, but does not permit transfer of noise and vibration into the passenger compartment. Do not replace the rubber mounts with solid ones.
  13. Before removing any component of the exhaust system, ALWAYS squirt a liquid rust dissolving agent onto the fasteners for ease of removal. A lot of knuckle skin will be saved by following this rule.

Make sure the system has cooled completely before spraying a liquid rust dissolvent. Most penetrating lubricants are also flammable.

  1. 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.
  3. When replacing a muffler and/or resonator, the tailpipe(s) should be checked. Often, the same wear or damage which caused a vehicle's muffler or resonator to fail will have taken the same toll on the tailpipe.
  5. When installing exhaust system parts, make sure there is enough clearance between the hot exhaust parts and pipes or 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.
  7. 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.

Click image to see an enlarged view

Fig. Fig. 1: View of a common system - exhaust flows from the manifolds and crossover pipe which leads to the catalytic converter, then exhaust enters the intermediate pipe

Be very careful when working on or near the catalytic converter. External temperatures can reach 1,500°F (816°C) and more, causing severe burns. Removal or installation should be performed only on a cold exhaust system.