A standard or stainless steel casing containing an array of baffles and other sound-insulating material to reduce exhaust noise. Some cars may use several mufflers, or a secondary muffler called a resonator.
The muffler reduces and changes engine exhaust sound and tone. When properly matched to the engine, a muffler will not impair engine performance due to exhaust backpressure, which is simply the resistance to exhaust flow.
Have your vehicle's exhaust system inspected periodically to keep your car safe. The muffler may not be individually replaceable due to the condition of other exhaust system components, or because the original exhaust system uses a unitized construction, where sections are welded together. Keep in mind that exhaust gas, especially carbon monoxide, can be deadly if it enters the interior of the car. The symptoms of an exhaust leak may include a louder than normal exhaust sound, the sound of exhaust coming from unusual places on your car, a “ticking” noise when accelerating, and the smell of exhaust. However, don't rely on your sense of smell as a conclusive means of determining if there' is an exhaust leak. Carbon monoxide has no odour. If you suspect any problem with the exhaust system, have it inspected immediately by a professional technician. Another symptom of a potential exhaust leak is a failed emissions test. A leak not only lets exhaust gas out, it also allows oxygen to enter the exhaust stream, which can be detected during an emissions test. You will usually be required to make repairs before retesting, so have the leak checked by a professional technician.