Eliot Silverman

Eliot Silverman

Tuesday, February 14, 2012

Exhaust System

I’m often asked how much it costs to replace or repair a muffler.  Not the easiest question to answer especially if the customer thinks the muffler is bad solely based on a loud exhaust.

We have all heard cars with broken exhaust systems.  Thy are obnoxiously loud! 

If you car is loud, it means one of the exhaust components are bad/broken.  A typical exhaust system has an exhaust manifold, exhaust pipes, catalytic converter, muffler and a tail pipe.  Typically but NOT all cars are like this.  Some cars have two mufflers, or the muffler and the tail pipe are one piece.  Some cars have a catalytic converter which is also the exhaust manifold, and some cars have two or four catalytic converters. 

The exhaust system is designed to quiet the car and to vent the engine’s exhaust fumes away from the occupants in the car.  If your exhaust system is broken, the car is obviously louder than is should be, but the exhaust fumes may vent into the car.  These fumes stink, and they are toxic. 

Most exhaust problems are caused by rust.  Rust east away and weakens metal exhaust parts.   This causes one or two problems.  Rust creates a hole in an exhaust part, or it can cause two parts to separate.    If there is a hole/separation in front of the muffler the car is louder than normal.  If there is a hole/separation behind the muffler, the car sounds normal, but you may be getting exhaust fumes inside the car. 

There are three reasons I hesitate giving a price on the phone to repair an exhaust system. 
1.        I don’t know if the part the customer wants replaced it truly the problem with the car.  I’m often asked how much it costs to replace the muffler when in fact, the muffler is good- another exhaust part has failed causing the car to be louder than normal.
2.       I need to see if I can replace just the bad part.  The part in front or behind the bad part can be so rusted that it will break it while removing the bad part. 
3.       While I can view a drawing of your exhaust system on my comput, it doesn’t always mesh with what is on your car.  At times my drawing shows two separate parts, but the car was manufactured with those two parts welded together.  Other times the “Muffler 4 Less” type of shop welded parts together.  Since I cannot un-weld parts, I need to replace both parts.  Welding is done because it is fast.  Bolting takes slightly more time, costs the same as welding: however, in the long run it will save you money. 

There are no maintenance requirements for your exhaust system.  There is nothing you can do to keep it from rusting, nor is there anything you can do to make it rust faster.  As long as Chicago uses salt in the winter, your exhaust parts will rust. 


  1. Nice description on exhaust system. After reading your post my knowledge about exhaust system has been increased.

  2. Hello, I was very encouraged to find this site. The reason being that this is such an informative post. I wanted to thank you for this informative read of the subject.
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  3. Does a catalytic converter also help muffle sound? Does component weight matter. i.e. is a heaver MOPAR muffler (34 lb.) quieter than a NAPA muffler (20 lb.)?

  4. Thank you very much for this useful article. I like it.
    brandon auto mechanic