You Have a Performance Muffler

• If you bought your car used and you find that the exhaust is louder than you expected, it may be because a previous owner installed a high performance exhaust. A performance muffler is designed to circulate more air and has less material inside the body of the muffler to deaden the sound of the exhaust. To determine if you have a performance muffler, you will probably need to take the car to a muffler shop where an expert can look at the muffler and tell you what kind it is.
  
  

Solution

• If it turns out that a performance muffler is the cause of your louder than desirable exhaust note, the only solution is to remove the muffler and install a stock muffler or a more restrictive one. This should be done by a muffler shop since it usually takes special tools and supplies to remove and install a muffler.
  
  

The Muffler Is Rusted

• One of the most common causes of a loud muffler is rust holes or corrosion caused by moisture or salt on the roads. If holes eat through the metal of the muffler, it will not muffle the sounds of the exhaust, resulting in excessive noise.
  
  

Solution

• Again, the only solution to a rusted muffler is to replace it with a new one. Mufflers are relatively inexpensive, and it is usually cheaper to simply replace an old one with a new one rather than trying to weld up or patch a rusty one. Plus, it's better in the long run to install a new muffler.
  
  

There Is an Exhaust Leak

• Another potential cause of a loud muffler is the presence of an exhaust leak where the exhaust pipe bolts or is welded to the muffler. If the seal between the exhaust pipe and the muffler is bad, the exhaust gases may be escaping, causing the muffler to be louder than normal.
  
  

Solution

• To determine if you have an exhaust leak near your muffler, raise the rear of the vehicle with a floor jack or crawl under the car near the muffler. Start the engine and listen for noises coming from the exhaust pipe. You can also use your hand to determine if there is any air blowing out from between the muffler and exhaust pipe. If there is a leak, have a muffler shop weld it up or install a new muffler clamp.