There are many noises associated with a muffler in need of maintenance, from rattling to popping under deceleration to a constant groan Some of these problems are easily repaired, others may require a professional, and some others are terminal and signal the need for a new muffler. These problems can be irritating and in some cases, dangerous--especially if your exhaust system decides to break loose and drag beneath your car in a shower of white-hot sparks.
Types and Function
A muffler's primary purpose is to silence the noise produced by a running engine, and it employs two primary means of doing so. Most mufflers contain a dense forest of fiberglass packing, which absorbs and dissipates the engine noise. Many performance applications use a baffled-style muffler and use a series of metal plates to modify sound. Baffled mufflers are fairly stout, but either of these can fail through either neglect or impact damage.
Metallic Rattling
Most stock mufflers employ a heat shield to protect nearby wiring and mechanical components. These exhaust shields are made of thin sheet metal and are designed to be held about 1/2-inch from the muffler by spacers. These heat shields can work loose over time, or can be dented by ground impact and left to rattle against the muffler surface. They sound like a tin can full of rocks when damaged, though they are easily repaired or replaced.
Exhaust Leaks
The welded seams that join the muffler to the exhaust pipe can crack over time, causing an exhaust leak. This is particularly prevalent on non-stock muffler installations that may or may not have been welded correctly. The solution is to re-weld the seam.
Be aware as well that the muffler itself may have developed a hole, due either to rust or impact damage. If there is no visible damage, check upstream at the catalytic converter or head-pipes.
Muffler Putty/Epoxy
Several products are available to silence exhaust leaks. The most widely used is muffler putty, which resembles orange toothpaste and hardens to fill leaking seams. Two-part epoxy like JB Weld can be used as well and may be suitable for larger cracks. However, neither putty nor epoxy should be used to repair large holes, as they will crack and fall free over time.
Repairing or Replacing
Some fiberglass-packing mufflers can be serviced by replacing the degraded packing with newer material. However, most mufflers are sealed from the factory and cannot be serviced, and so must be replaced..
Tags: over time, easily repaired, impact damage
