Many of today’s cars are so sophisticated that you need your owner’s manual to decipher even something simple, like your stereo system. Exhaust system mufflers, however, are still (thankfully) pretty simple. It doesn’t take special training or an automotive computer diagnostic system to let you know that there’s a problem. When you understand what a muffler is and how it works, it’s easy to know when it’s time to let a professional take a look.
A muffler is a device that reduces the exhaust sounds created by your car’s internal combustion engine. They reduce noise by routing sound through a series of passages and chambers until the opposing sound waves are absorbed and cancelled. However, the muffler and the rest of the exhaust system do more than just reduce noise.
An exhaust system must also funnel exhaust gases away from the passenger compartment. Exhaust gases contain carbon monoxide, nitrogen and sulfur oxies, and other byproducts of burning gasoline and diesel that are bad for your health. Carbon monoxide, in fact, is potentially lethal in that it reduces your body’s ability to absorb and transport oxygen. Prolonged exposure to carbon monoxide gas (which is colorless and odorless) can cause nausea, headaches, loss of consciousness, and even death. Therefore, taking care of your exhaust system is important – it’s not just about sound, it’s about safety too.
So how do we know when our muffler is behaving normally or if it needs to be replaced?
If you drive a high-performance muscle car, you can expect to hear a throaty growl from your muffler. For the rest of us, a loud muffler or one that that is noticeably louder than in the past, usually means that you have problem. Holes are common in exhaust systems on older vehicles, and because holes leak out toxic exhaust gases, this is a potentially dangerous situation. Additionally, a loud muffler can also grab the attention of your local law enforcement officials. Many municipalities have noise ordinances and issue hefty tickets for noisy mufflers.
If your muffler isn’t any louder than it used to be, but you hear a new noise like rattling and/or ticking, that could also be a problem. A rattling sound may mean that your exhaust system is loose or misaligned. Rattles are often serious (you don’t want a loose part of your exhaust system to fall off your car), so they should be checked out by a qualified technician as soon as possible.
A ticking sound coming from underneath your car can be normal, especially after you park your car. As hot metal parts in your exhaust system cool, they often make a ticking noise. However, if you hear a new ticking noise that you didn’t hear before, that could be a symptom of a problem in another part of the exhaust system such as a loose exhaust manifold.
Remember: mufflers and exhaust systems with holes or cracks can allow exhaust fumes and carbon monoxide to enter your passenger compartment. For this reason, it’s important to pay attention to the sounds your car makes and take it in for an inspection if you hear something you’ve never heard before.