If you’re reading this post, you’ve probably got a broken muffler in your car. You’ve probably already got an estimate from your mechanic, but you’re probably wondering, is the estimate correct? Or is your mechanic ripping you off? Well, we’re going to inform you more about a car’s muffler repair cost in this post. As well as the signs of a bad muffler so that you can confirm if you really have a muffler problem or not. Additionally, we’ll guide you on how to repair it yourself should you need to save some money.
What’s a Muffler?
As always, we like to begin with what a car part actually does and how it works before we get into the business of repairing it. It’s a good idea to understand more about your car’s muffler, so you can make better and informed decisions for your car’s muffler repair cost. So, what’s a muffler? A muffler is part of a vehicle’s exhaust system. It’s designed to reduce the noise made by a vehicle’s exhaust system, making the driving experience quieter and smoother.
Without a muffler, there will be no filter for the noise that a car makes. Most cars typically have a humming noise coming from the engine and a very slight roar from the exhaust. This is thanks to the muffler muffling the sound coming from your exhaust system. Without it, or if the muffler is broken, then your car will sound much rougher as there’s no device filtering the noise.
You can find your car’s muffler at the back of your car. It’s usually an oval-shaped chamber that sits behind the car’s exhaust tips and underneath the rear bumper.
Is the Muffler the Same as the Catalytic Converter?
The confusion is understandable. Both devices sit underneath the car and have a similar tubular or oval shape. To make it worse, some articles use images of a muffler for illustrating the catalytic converter. But the two are different components in your car’s exhaust system.
The catalytic converter sits somewhere at the center of your car’s underbody, right in the middle of the exhaust system. It’s responsible for converting the engine’s emission to less harmful and toxic gases. Meanwhile, as mentioned, the muffler sits at the end of the exhaust system and is used for reducing the noise the exhaust system makes. We wrote a great article about catalytic converters and their replacement cost and you can read more about them here.
Now you know what’s a muffler is for, but how does it work? Well, it depends on what type of muffler that you have in your car.
Types of Mufflers
There are various muffler designs and they use different materials depending on the manufacturer. But there are generally four common types of mufflers:
Despite the name, turbo mufflers are not just for cars with turbochargers, any car can use them. In fact, they’re one of the most common types of mufflers in production cars. There’s a series of conflicting information online on why they’re called turbo mufflers, but it seems that it’s because they were often associated with the turbocharged Corvair of the 1960s, which has a different muffler construction compared to other OEM mufflers at the time.
Anyway, let’s not dwell on confusing nomenclature. Turbo mufflers have a series of perforated pipes within them, usually laid out in an S-shape, which feeds the gases back and forth within the muffler. The exhaust gas will enter through one pipe, entering a chamber, then travel through another pipe into a different chamber, before finally entering another pipe to flow into the rear chamber and finally exiting it.
All this bouncing and traveling through the pipes reduces the exhaust gas flow, making them quieter. Additionally, the chambers are sound-canceling plates or baffles, which helps in absorbing the noise. However, this design inherently restricts the flow of the exhaust gas. While this makes them incredibly efficient in absorbing sound, they’re not great for performance. This is because of backpressure, which we will discuss later on in the performance muffler section.
Multiple Baffle or Chambered Mufflers
The second common type of exhaust muffler is the multiple baffle muffler, or sometimes also called chambered muffler. As the name suggests, the muffler has multiple chambers within it. The chambers themselves are created by using sound-canceling plates, also known as baffles. When exhaust gases hit and bounce off the baffles, the sound will be muffled, resulting in quieter exhaust noise.
They are largely similar to turbo mufflers. However, since the exhaust gases don’t have to travel through a series of perforated pipes, the exhaust gas can flow more freely. This results in less restriction, and therefore better performance. But they won’t be able to lower the noise as well as turbo mufflers.
Straight-through mufflers usually have a tubular shape. Within it lies a tube for the exhaust gas to flow straight through the muffler, with glass fiber wrapped around it and an insulator. The glass fiber and insulator are what absorb the noise from the exhaust. But since there are no sound-canceling chambers and the exhaust gas flows freely, straight-through mufflers are less efficient in absorbing noise and therefore louder than other types of mufflers.
When designed correctly, straight-through mufflers can allow more performance since it’s a lot less restrictive. However, they will often result in a loud and rough noise. The noise characteristic will depend heavily on your engine layout. Car enthusiasts going after a loud noise from their exhaust pipes will often go for straight-through mufflers when modifying their cars. Straight-through mufflers are great when you just want your car to make more noise, but your neighbor probably won’t appreciate it.
This is not to be confused with the term straight-pipe or straight-piping your exhaust. Straight pipe is when you replace the catalytic converter and the muffler with a single pipe, so there’s no filter from the exhaust headers to the tips. Hence why it’s called a straight-pipe. This results in unfiltered exhaust gases and therefore louder noise, and sometimes more performance. Keep in mind that it’s actually illegal to drive a car without a catalytic converter.
Performance mufflers are usually a variation of chambered or straight-through mufflers. The main difference is that performance mufflers have a resonance chamber. This chamber is designed to amplify the noise that your car makes, making them sound louder and – most of the time – better. Additionally, they usually allow for less restricted gas flow, which creates even more noise and less exhaust backpressure which leads to better performance.
What’s exhaust backpressure, you ask? Exhaust backpressure is when the car’s exhaust gas isn’t flowing freely through the exhaust system and creates pressure back into the engine’s cylinder. This can cause exhaust gases to remain inside the engine’s cylinder, taking up space for fuel and air. This means that the engine won’t be able to burn as much fuel and air as it needs, resulting in less horsepower. This is why performance mufflers usually have a less restrictive design so that they can minimize backpressure.
The design of performance mufflers depends on the manufacturer since each manufacturer wants to create mufflers with a unique sound characteristic. Borla mufflers for example usually have a more rumbly noise, while Flowmaster mufflers often have a clearer and crisper sound. Most mufflers are usually made from aluminized steel or stainless steel, although some performance mufflers are made from titanium.
Additionally, some performance mufflers now often have vacuum valve technology. These valves can open and shut, altering sound and performance. When it’s closed, the exhaust will sound quieter with better torque performance. But open the valves and the exhaust will have an entirely different sound characteristic and provide better performance at higher RPMs.
You can learn more about how exhaust systems work in the video below. It’s a bit lengthy, but it will give you a clear understanding of the inner workings of the exhaust muffler:
Muffler Repair Cost: Signs of a Failing Car Muffler
Before we get into the muffler repair cost, let’s talk about the signs that you will see when your muffler is failing. Keep in mind that these signs could mean there’s a problem with the exhaust system as a whole and not just the muffler. You will need to inspect the exhaust system to verify the root of the problem.
Loud Exhaust Noise
The most obvious sign that you’re likely to notice is a change in the exhaust noise that your car produces. Most cars are relatively quiet, with a slight roar coming from the exhaust that you can barely hear. When the muffler corrodes or there are cracks in the exhaust system, your exhaust note will be louder and likely sound a lot rougher. In some cases, it may even sound like your car has an old truck engine.
A muffler will corrode over time, and its internals will break down as well, making it less efficient in absorbing noise. Meanwhile, cracks or leaks in the exhaust system mean the exhaust gases will escape from places where they shouldn’t, emitting unfiltered exhaust noises.
Check where the noise is coming from. If it’s coming from the front, then it may be a header or exhaust manifold issue. If the noise is coming from the middle, then you probably have an exhaust leak somewhere in the mid-pipes. And finally, if the noise is coming from the back of the car, then it’s likely a muffler issue. You can check by jacking up your car to give you more room and then get underneath it. Then check for visible cracks or leaks throughout the exhaust system. If you can’t find it, we recommend going to a trusted auto repair shop and have a mechanic inspect your car.
One last note, it’s also possible that you’re hearing a banging or knocking noise. In this case, it’s possible that one of your exhaust mounts has come loose and your muffler and tailpipes are dragging along the ground. If this happens, you will need to reinstall it and replace the mounts. Additionally, you need to check your muffler and exhaust pipes for signs of damage.
Sound is essentially the vibration of air, that’s basically how sound travels. So, when you have an exhaust or muffler leak, it will make more vibration than usual. You may not notice this symptom as the leak may be small and the vibration it makes may not be enough to affect the whole car. However, if the leak is big enough, you may feel more vibration than usual when you rev the engine. If you notice the car vibrating and making a louder noise than usual, you will definitely need to check your mufflers and the exhaust system.
Strong Gas Smell
The most serious sign that you will see – or smell, to be precise – is the stench of noxious gases suddenly appearing in your vehicle. When you have an exhaust leak, the exhaust gases may escape and seep into your vehicle’s cabin. If the smell is particularly strong, you likely have a leak before the catalytic converter. This is because the exhaust gas wouldn’t have had a chance to get filtered first by the catalytic converter.
In any case, this is a serious problem that you will need to address immediately. These gases are poisonous and can lead to serious health problems. Inspect your exhaust system for leaks if you smell any noxious gas in your car.
Bad Fuel Mileage
Okay, this last symptom isn’t exactly a sign of a muffler problem, but it could be a symptom of an exhaust system problem so we’re going to include it anyway. There are tons of possible reasons why your car is getting bad gas mileage, including an exhaust leak. Specifically, when the leak is located before the catalytic converter. If the leak is located after the catalytic converter or on the muffler, it’s unlikely to affect gas mileage.
How does this happen, you ask? First, you need to understand more about your car’s exhaust system: the exhaust system has an oxygen sensor that’s usually located in the exhaust manifold and just before the catalytic converter. As the name suggests, this sensor monitors the amount of oxygen in the exhaust gases. When it detects a high amount of oxygen, the car’s Engine Control Unit (ECU) will assume the engine is running on a lean fuel and air mixture (less fuel, more oxygen). In this case, the ECU will inject more fuel into the cylinders to balance the mixture.
A vehicle’s engine needs to run on a balanced mixture because, in certain scenarios, a lean mixture can damage the engine. So, how does an exhaust leak affect this? Well, when you have an exhaust leak, oxygen from outside will enter the exhaust system. If the leak is located before the oxygen sensor, this will lead the sensors to believe that your engine is running on a lean mixture. It will then tell the ECU to inject more fuel, resulting in more fuel being used when it actually isn’t necessary.
Muffler Repair Cost
So, now that you understand how mufflers work and the signs of a broken muffler, let’s discuss the muffler repair cost. When you have a broken muffler, there are two possible repairs that you can do. First, if you have a minor leak on the muffler, you can patch the leak. You can do this yourself by applying epoxy to cover the leak. Or if you don’t feel like getting your hands dirty, an auto repair shop should be able to do this for you. They may use either epoxy or weld on a patch to the muffler. Either way, this keeps muffler repair costs at a minimum, usually around $50 – $150. However, this is only a temporary fix. Once cracks start to appear, it’s likely more will appear as your muffler is already starting to rust.
If you have a leak on your muffler and it’s over five years old, you might want to replace it entirely. Most mufflers last around five to seven years, but some can last much longer. But if it’s around this age you might as well replace it since the internals is probably already rusting away. As with any other car part, the cost varies depending on the make and model.
An OEM exhaust muffler usually costs between $250 – $400. On average, you can expect to pay about $350 for a new muffler, add labor cost of about $100, and that brings your muffler repair cost to about $450. If you drive older cars with less complex mufflers, you can expect the cost to be much cheaper. For example, we found out that the exhaust muffler for a 1970s Toyota Land Cruiser costs just $83. Needless to say, luxury and performance vehicles will cost more, sometimes up to $800 for a brand new muffler.
Muffler Repair Cost: Should I Buy Aftermarket Mufflers?
Before we get into the DIY repairs, another way you can save money is to buy aftermarket mufflers rather than OEMs. OEM stands for Original Equipment Manufacturer, this basically means the part is made by the car manufacturer themselves. This also means the part will fit perfectly with your vehicle, but OEM parts tend to be quite expensive.
Meanwhile, aftermarket mufflers are made by third-party manufacturers that are not related to the car manufacturer. Oftentimes, they will be quite a lot cheaper, especially if they’re not performance-oriented products. Even some mufflers from a well-known company such as Borla only costs around $90. So, should you buy aftermarket then?
Sure, but there are a few things you need to note. First, before you make your purchase, make sure that the muffler you’re buying will fit in your car. There’s no point buying an aftermarket muffler that’s much cheaper than OEM only to find out it doesn’t fit your car’s exhaust system.
Secondly, research the part and how it will affect your car. Most aftermarket mufflers will give your car a different – and often louder – exhaust note. If you don’t want a loud growling car, be sure to buy an aftermarket muffler that focuses on being silent and efficient, not loudness and performance. And finally, it’s always a good idea to buy aftermarket products that come with a warranty.
Muffler Repair Cost: Can I Drive without a Muffler?
Well, technically, you can, but you shouldn’t. While a broken muffler or driving without a muffler won’t really affect or damage your engine, it’s really not recommended. The loud noise will be unpleasant and neither you nor your neighbors will like it. Additionally, as mentioned earlier, a broken muffler can result in an exhaust gas leak that seeps into your car’s cabin. This is especially dangerous and can lead to serious health problems.
And of course, there are legal issues. While – as far as we can tell – there’s no law prohibiting you from driving without a muffler, there are exhaust noise laws that you may break when your car is running without a muffler. Not to mention, your car may not pass an inspection. Best to replace that broken muffler to stay on the good side of the law, even if the muffler repair cost is a bit steep. Bottom line: don’t drive without a muffler.
Saving Money on Muffler Repair Cost: DIY
As mentioned, you can patch your muffler with epoxy or weld a patch if there’s a minor leak. This is much cheaper and will save you a ton of money. But if you have no choice but to replace the muffler, then buying aftermarket rather than OEM can help save money. And of course, the next way to save money on muffler repair costs is to do the job yourself. Here’s a quick guide:
- Park your car and lift it with a car jack. Use wheel chocks to prevent the car from moving.
- Remove the muffler clamp bolts. The muffler clamp connects the muffler to the exhaust pipe; remove the bolts, and then you can slide it out. Use penetrating fluid such as WD-40 to help undo the bolts.
- Mufflers will usually have their own hangers or brackets as well to hold them in place. Remove these hangers or brackets so you can unmount the muffler from your car.
- Place the new muffler by connecting them to the exhaust pipe first and then put the clamp back on. Hand-tighten the clamp bolts first so you can adjust the new muffler to sit correctly on the hanger or bracket.
- Once the new muffler is sitting correctly, tighten the clamp bolts properly. Make sure the muffler is not moving around anymore.
- Once you’re done, start the engine and check if there are any exhaust leaks.
The process will be slightly different depending on your car’s make and model. But in general, what you need to do is remove the clamps, slide the muffler out, install the new muffler, and tighten back the clamps and brackets. Here’s a quick video from Scotty Kilmer on how to replace a car muffler:
Muffler Repair Cost: Wrap Up
Mufflers are a sound-canceling device to reduce the sound your exhaust system makes. While your engine will probably run just fine with a broken muffler, it’s still recommended to repair or replace it when you need to. You can opt to patch minor leaks to keep muffler repair costs at a minimum. If you have no option but to replace it, then buying aftermarket and doing the job yourself is a great way to keep muffler repair cost down.
These tools have been tried and tested by our team, they are ideal for fixing your car at home.