Signs and Symptoms of a Bad Muffler – Now From Nationwide

June 27, 2022
Stressed woman driver sitting inside her car

Signs Your Muffler is Bad and Needs to Be Replaced

You enjoy listening to tunes in the car, but lately it’s becoming harder to hear the music. Is it your imagination or the muffler? You figure you’ll wait and see.

This may not be the best move because mufflers are all about safety.

What is a muffler and what does it do?

While we rarely think about mufflers until there is a possible issue, they actually perform several vital functions. Mufflers, or silencers, are devices that reduce sounds by absorbing sound waves and directing them through different passages. In addition, they channel away harmful carbon dioxide and other exhaust fumes that result from the burning of gasoline. [1]

Breathing in carbon monoxide in particular has the potential to be deadly. Passengers have no way to know this is happening since it is colorless and odorless. The carbon monoxide actually interferes with the body’s ability to transport oxygen, which can result in a variety of symptoms after lengthy exposure, including headaches, nausea; and loss of consciousness, which can ultimately be fatal.

Muffler vs. exhaust system: What’s the difference?

An exhaust system is made of several parts that work together to minimize noise and help exhaust gases exit the engine, keeping you and your passengers from getting sick. Exhaust systems include an exhaust manifold, a catalytic converter, a resonator, a tailpipe and a muffler. [3]

The muffler is integral in ensuring that the power needed to compress the pistons is sufficient to rotate the wheels. This controls the speed at which the exhaust fumes move out of the system. When the compression function is not working properly, the vehicle can begin to get poor gas mileage or stall out.

Symptoms of a bad muffler

Loud muffler sound

What does a bad muffler sound like? The most common tipoff is noise. If your vehicle is usually quiet and now you hear it rumble, don’t turn up the radio; instead check the muffler. [3] If you have a muffler with a hole in it, you may hear a rumbling noise. [2] If you let it go long enough, you may even get ticketed for violating noise ordinances.

A rattling car muffler sound is another warning sound—a tipoff that your exhaust system is coming loose and is no longer correctly aligned. Even worse, the muffler can sometimes drop down and drag along the ground. In either case, the time has come to have this worked on by a professional.

Low gas mileage

One of the signs the muffler is no longer working properly can be a decrease in gas mileage. If you find yourself suddenly filling up your tank more often, one possibility is your muffler. [3]

Also, you may notice the smell of exhaust fumes coming your way. If gases are escaping through holes in the muffler and coming back into the car, the problem is extremely serious and should be immediately fixed. [3]

When to repair or replace your car’s muffler

You may be wondering how long do mufflers last? The life span of a muffler can vary from car to car depending on the car model and how frequently the car is used. A car that has been driven more miles will have more wear and tear on the undercarriage of the vehicle where the muffler is housed, and wet climates and snow can also exacerbate wear. But in average driving conditions a muffler will last about 40,000 to 80,000 miles or 2 to 4 years. [3]

A rattling noise, low gas mileage and the smell of exhaust fumes are all indicators that your muffler needs to be replaced. Replacing a muffler costs around $800 and may vary depending on where you live.

If you think your muffler may be the source of the mounting noise, take the issue seriously and promptly get it checked out. You’ll also want to make sure you’re covered in the event of a muffler problem. Find out how Nationwide Car Insurance can keep you and your car safe.

[1] “Exhaust Muffler Replacement Cost,” (accessed April 12, 2022)

[2] (accessed April 12, 2022)

[3] (accessed April 12, 2022)


The information included is designed for informational purposes only. It is not legal, tax, financial or any other sort of advice, nor is it a substitute for such advice. The information may not apply to your specific situation. We have tried to make sure the information is accurate, but it could be outdated or even inaccurate in parts. It is the reader’s responsibility to comply with any applicable local, state or federal regulations. Nationwide Mutual Insurance Company, its affiliates and their employees make no warranties about the information nor guarantee of results, and they assume no liability in connection with the information provided. Nationwide, and the Nationwide N and Eagle are service marks of Nationwide Mutual Insurance Company. © 2022 Nationwide

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