5 Symptoms of a Hole in Your Muffler or Exhaust

If you drive in areas where road salt is used in winter or near the ocean, your muffler may be affected by corrosion which eventually can cause a hole to develop in the metal. When this happens, muffler replacement becomes necessary.

Since regular, comprehensive inspections of a muffler isn’t something most of us will do, let’s look at the most common symptoms you’ll experience when there’s a hole in your muffler or exhaust.

hole in muffler symptoms

Common Hole in Muffler Symptoms

When a hole begins to form in your muffler or other exhaust system component, there are some warning signs that you need to be paying attention to.

As soon as you notice these symptoms, you’ll want to make a trip to a reputable muffler/exhaust repair shop or a service appointment with a trusted auto repair shop or dealership. Here are five of the most common signs to look for.

#1 – Loud Noises

noise while driving

Obviously, the number one symptom of a hole in the muffler is noise. Since a functioning muffler is supposed to reduce noise, a muffler with a hole in it will fail at its job. This means the noises that would normally be reduced will now be louder… much louder.

If you don’t replace the muffler soon, the hole will only expand and get bigger in the muffler. Then, these rumbling sounds will grow louder at the same time. Since working mufflers are required by law in most areas, you risk being pulled over by the police and getting an expensive citation.

Related: How to Make Your Exhaust Louder or Backfire

#2 – Carbon Monoxide

tire noise

The muffler prevents carbon monoxide from the exhaust gases to get into the interior cabin where everyone sits in the vehicle. But if the muffler has a hole in it, you have an exhaust leak where the carbon monoxide will be able to find its way into the cabin.

The scary thing is that you won’t be able to smell, see or taste this toxic gas. Instead, you will just feel the effects of it. Some of these effects include dizziness, headaches, tiredness, and trouble breathing. If you breathe it in for too long, it can lead to death.

#3 – Emissions Test Failure

emissions test failure

You cannot see carbon emissions when they come out of your tailpipe, but they are there. White smoke coming out of your exhaust doesn’t necessarily mean excess emissions. The only way to know if you’re producing fewer carbon emissions is to get an emissions test.

Most states require you to get these tests while some do not. If you happen to live in a state that requires you to get the test and then you end up failing it, this could be due to a hole in the muffler.

See Also: Straight Pipe Exhausts (Pros/Cons)

#4 – Rust Holes

rust hole in exhaust

Mufflers normally have small holes called “weep holes.” The purpose of these holes is to let water drain out of the muffler so that rust does not form. But if you see rust holes forming close to the exhaust pipes, these are not the weep holes. Anytime you see rust holes, you need to be worried.

Related: Causes of Water Coming Out of Your Exhaust

#5 – Engine Misfires

cylinder misfire causes

It is important for the entire exhaust system to be functional to ensure the engine runs smoothly. If just one component of the exhaust system is damaged or worn out, then it can cause an engine misfire. A hole in the muffler is one possible way your engine could misfire.

What is the Purpose of a Muffler?

purpose of a car muffler

A car muffler actually serves three main purposes. The first purpose is to lower the amount of noise that is generated by the exhaust system. The muffler redirects this noise so that it goes out of the exhaust pipes. That way, the passengers and everyone close to the vehicle will not be annoyed by these noises.

A second purpose of it and the rest of the exhaust system is that it allows the exhaust gases from the internal combustion engine to flow away from the engine. Not only does this protect the passengers from dangerous exhaust fumes created by the engine, it allows exhaust gases to cool via expansion and will prevent any spark or flame from the engine from coming out of the exhaust.

The third purpose of a car muffler is to maximize engine performance. The proper burning of fuel and air inside the combustion chamber is what produces power. The job of the exhaust system and muffler is to keep the exhaust vapors moving so more fresh air/oxygen can be sucked into the engine to produce more power.

See Also: Pros/Cons of a Muffler Delete

What Causes a Hole in Your Muffler?

As already mentioned, salt is the enemy of mufflers and your exhaust system in general whether it’s from road salt use or living near the ocean. This can result in corrosion and a hole developing. But another danger exists.

Regularly driving through potholes or going too fast over speed speed bumps can cause damage to your muffler. The longer you put your vehicle under these conditions, the more likely that your muffler will suffer for it.

The result can a small dent, tear, or actually ripping a hole into an exhaust component. Once that happens, it will fail to do its job properly.

Read Also: Resonator vs Muffler

Mark Stevens


  1. Oh wow, thank you very much for mentioning about the importance of a muffler in reducing sound pollution from our vehicles. My son just bought an used car last month for his daily commute to college and he wants to keep it in good condition. I’ll ask him to look further into this matter when he sends it for a maintenance later.

  2. Some string like stuff is coming out my exhaust I have pulled a lot out but it still keeps coming out again is it dangerous and what can I do to stop it

    1. Can you describe the stuff in more detail? Nothing stringy should be coming out of the exhaust. Since I have no idea what it is, I can’t say if it could be dangerous or not. Have someone check it out in person if you have any doubts.

    2. What kind of car do you have? Some use fiberglass packing in the muffler (like my Volvo), and it’s not unheard of for it to come out of the exhaust when you’re experiencing problems. If the string like stuff looks like strands of hair, that could be it.

  3. My friend pit a str as ight pipe on my car and left the muffler on…my car wont run and its misfiring. Can you straight pipe and leave on the muffler

    1. It’s possible, but it may not be legal. A “straight pipe” typically refers to an exhaust with no catalytic converters, resonators, or mufflers. In this case it sounds like your friend just deleted the catalytic converter(s). Check your local emissions laws to see if this is allowed. If you have to take a smog test, you will almost certainly fail without catalytic converters.

      I’m not sure if this is related to the misfires or not. Is your car throwing any codes?

Leave a Reply

Your email address will not be published. Required fields are marked *