Exhaust system service is usually needed when a component in the system rusts and begins to leak. Because engine combustion produces water and acids, an exhaust system can fail in a relatively short time.
Danger! A leaking exhaust system could harm the passengers of a car. Since engine exhaust is poisonous, a leaky exhaust can allow toxic gases to flow through opening in the body and into passenger compartment.
Exhaust system inspection
To inspect an exhaust system, raise the car on a hoist. Using a lead light, closely inspect the system for problems (rusting, loose connections, leaks). In particular, check around the muffler, all pipe connections, gaskets, and pipe bends.
Danger! Parts of the exhaust system especially the catalytic converter, can be VERY HOT. Remember not to touch any component until after it has cooled.
Exhaust system repairs
Faulty exhaust system components must be removed and renewed. If only the muffler is rusted, a new muffler can be installed in the existing system. After prolonged service, several parts or ALL of the exhaust system may require renewal.
When repairing an exhaust system, remember the following:
- USE RUST PENETRANT on all threaded fasteners that will be reused, Fig. 22-6. This is especially important on the exhaust manifold flange nuts or bolts.
- Use an air chisel, cut-off tool, cutting torch, or hacksaw to remove faulty parts. Make sure you do NOT damage parts that will be reused. See Fig. 22-7 for some examples.
- A SIX POINT SOCKET and ratchet or air impact will be usually allow quick fastener removal without rounding the fastener heads. Refer to Fig. 22-8
- Wear SAFETY GLASSES or goggles to keep rust and dirt from entering your eyes
- Obtain the correct replacements parts.
- A pipe expander should be used to enlarge pipe ends, as needed, Fig.22-9. A pipe sharper can be used to straighten dented pipe ends, Fig.22-10
- Double-check the routing of the exhaust system. Keep adequate clearance between it, the car body, and chassis. See Fig. 22-12
- Tighten all clamps and hangers evenly. Torque the fasteners only enough to hold the parts. Over-tightening will squash and deform the pipes, possibly causing leakage.
- When replacing an exhaust manifold, use a gasket and check sealing surface flatness. If the manifold is warped, it must be machined flat. Torque the exhaust manifold bolts to specs, Fig.22-13
- Always use new gaskets and O-rings.
- Check heat riser operation using the information in a service manual
- Install all heat shields
- Check the system for leaks and rattles after repairs