Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Muffler

muffler

Bad or Failing Muffler Inspection

by a top-rated mechanic at your home or office

Did you know that the first internal combustion engine had a muffler installed? Although it wasn't up to today's standards, nor was it designed to reduce emissions or sound, the first combustion engine developed by J. J. Étienne Lenoi in 1859 had a small metal reducer on the end of the exhaust designed to reduce backfiring. Since those early days, mufflers have evolved and have become required components on any vehicle that operates on roads in the United States.

Today's mufflers serve two functions:

  • To reduce exhaust system noise that is directed from exhaust ports to the exhaust pipes
  • To help direct exhaust gases out of the engine

A common misconception is that mufflers are also an important part of vehicle emissions. Although there are chambers located inside the muffler that help to break up particulate matter emissions, the emissions control is the duty of catalytic converters; which are installed prior to the rear muffler and can reduce dangerous chemical emissions coming from the rear of today's combustion engines. When mufflers become worn out, they typically lose their ability to effectively "muffle" the sound of the vehicle's exhaust.

Mufflers typically last five to seven years on most US vehicles, but can become worn out prematurely due to several issues including:

  • Being exposed to salt; either on roads that are commonly iced or snowy or saltwater in communities near oceans.
  • Being frequently hit due to speed bumps, low clearance pot holes, or other impact items.
  • Excessive use or custom fabrication that is not recommended by the manufacturer.

Regardless of the precise cause, broken mufflers typically exhibit a few common symptoms that will alert the vehicle's owner that a problem exists and needs to be repaired or replaced by an ASE certified technician. Noted below are a few of the warning signs of a broken, bad, or failing muffler that should be replaced.

HAVE SYMPTOMS OF CAR TROUBLE?
Get an $80 diagnostic
by a top-rated mechanic at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

1. Engine is misfiring

Today's engines are finely tuned machines, where all components must work together in conjunction in order to work effectively and efficiently. One of these systems is the vehicle's exhaust which begins at the exhaust valve chamber inside the cylinder head, flows to the exhaust headers, into the exhaust pipes, then to the catalytic converter, to the muffler, and out the exhaust pipe. When any of these components are damaged, it can impact vehicle performance, including causing engine misfiring. If the muffler has a hole inside the unit and loses its efficiency, it can cause misfiring in the engine, particularly when under deceleration.

2. Exhaust is louder than normal

Loud exhaust noise is usually the result of an exhaust leak that commonly occurs in the muffler as opposed to the exhaust components located near the engine. As engine exhaust flows through the exhaust system, it is contained and eventually flows through the muffler. Inside the muffler is a series of chambers that helps to reduce the vibrations coming through the exhaust which is commonly associated with sound. When the muffler is damaged or has a hole in it, this causes the pre-muffled exhaust to leak, increasing the sound that comes out of the exhaust system.

Although it is possible that exhaust leaks can occur before the muffler, in most cases, loud exhaust is caused by a leak in the muffler itself. In either case, a certified mechanic will need to inspect and repair this issue.

HAVE SYMPTOMS OF CAR TROUBLE?
Get your car fixed at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

3. Condensation from the exhaust pipes

When the exhaust system, including the muffler, cools down from the engine being run, the moisture in the air condenses inside the exhaust pipe and the muffler. This moisture sits there and slowly eats away at the exhaust pipe and the shell of the muffler. Over time and countless warm up/cool down cycles, the exhaust pipe and the seams of your muffler rust out and start to leak exhaust gases and noise. When you notice excessive condensation coming from the exhaust pipe, especially in mid-day or warmer periods of the day, this may be a signal that the muffler is starting to wear out.

As the muffler is a critical component of the complete operation of your vehicle, any of the above warning signs should be taken seriously and inspire you to contact a local ASE certified mechanics as soon as possible.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...


Related questions

Q: Exhaust system repair - do I need new gaskets?

It depends on what the material of the gaskets are made of. Gaskets are fairly cheap, so I recommend replacing them. Your other option is to inspect them once the exhaust system is disassembled. If they are a thin...

Q: Performance issues when driving and idling, RPM dropping abruptly

The symptoms you are describing are almost always caused by a bad catalytic converter. When this fails it clogs the exhaust, which causes these problems to occur. Do a back pressure test on the exhaust first. If that is fine...

Q: Loud, hot-rod type sound when driving

Hello. It sounds like the catalytic converter gaskets may be causing a leak in the exhaust system. It is also possible that there is a leak or bad baffle in the muffler. This may be causing the hot-rod sound. It...