The exhaust system is one of the most vital systems that are integrated in vehicles. Its main function is to transmit the burnt gases, which came from the internal combustion engine, to the exhaust pipe. If these burnt gases do not escape from the engine immediately through the exhaust system, the engine may choke up and eventually breakdown. But aside from this function, the exhaust system has another important function which is to reduce the noise generated by the engine. To do this, the system allows the burnt gases, which escaped directly from the engine, to pass through metal plates and tubes called the muffler. Muffler is a device used in reducing the tremendous amount of noise that the engine produces. This is often located along the exhaust pipe of the engine or underneath the vehicle at the rear; but in freighter trucks, a vertically mounted muffler is used behind the cab. This consists of a backbox, which is designed mainly to receive the pressure waves and bounce them around inside the cylinders and chamber called the resonator, and one or more tailpipes. When these pressure waves collide with one another, the waves of equal but opposite amplitude will cancel each other out. And this destructive interference in the muffler now leads to the majority of the noise reduction. But since the location of the muffler is on the undercarriage, this is often neglected. Keep in mind that a muffler in poor condition can cause any vehicle to fail the state-required smog tests. That is why it is really important to regularly check and maintain this part. If you are a vehicle owner, it is a must that you take a peek at your muffler from time to time to make sure that it is in good condition. When you fail to do this, it will rust out over time, rot, and eventually fall of your vehicle. You can avoid this from happening if you just observe regular muffler check and maintenance.