4 Common Exhaust Leak Symptoms (& Repair Cost)

When everything is going right with your exhaust system, it’s a part of your vehicle you really don’t even think twice about. But while many people think of an exhaust system as nothing more than a metal pipe that pushes the exhaust out of the back of your vehicle, there’s more to them than that.

Modern exhaust systems are complex systems that improve engine performance, reduce emissions, and keep your vehicle legal to drive on public streets. So, if your vehicle has an exhaust leak you need to figure out what’s happening.

It’s an important job, which is why we highlighted some of the most common symptoms and causes of exhaust leaks here. Not only that, but we broke down everything you need to know to fix an exhaust leak if one does crop up on your vehicle!

4 Exhaust Leak Symptoms

If your vehicle has an exhaust leak, it’s a problem. But you won’t know about the problem until it’s had the chance to spread and create even more damage if you don’t know about any of the potential symptoms.

That’s why we took the time to highlight four of the most common exhaust leak symptoms for you here. If you notice any of these things coming from your vehicle, you need to look even further to figure out what’s going on.

1. Hissing Sound at Higher RPMs

This is by far the most common symptom of an exhaust leak. And while the hissing sound is far more noticeable at higher RPMs, if you know what you’re listening for you should be able to notice it at lower RPMs too.

This hissing sound is the sound of the exhaust rushing out of the hole in the exhaust system. The larger the hole the louder the noise. But while normally the noise is a hissing sound, if the hole is large enough it’ll sound more like a rumble than a hiss.

2. Unusual Odor

Where and how much you’ll notice an odor from an exhaust leak all depends on where the exhaust leak is and how bad it is. To notice an odor you typically need to have a pretty severe exhaust leak. If the exhaust leak is farther up the exhaust you might start to notice it in the cab, but it’s pretty unlikely.

It’s more likely that you’ll start to notice the smell of exhaust farther back, and it’ll often be a little stronger than the typical exhaust.

3. Check Engine Light

This is one of the less likely symptoms of an exhaust leak, but depending on where the exhaust leak is at, it’s possible. In order for a check engine light to turn on the vehicle needs to have a severe enough exhaust leak before the oxygen sensors.

A bad enough exhaust leak before the oxygen sensors will throw off the readings for the sensors, which will lead to the check engine light. Moreover, if the leak throws off the readings from the oxygen sensors it’s likely your vehicle will experience a few performance problems as well.

You might see a small dip in power and a small drop in fuel efficiency. However, unless you’re specifically looking for these things, you’re not likely to notice much of a difference since it should be a pretty nominal drop in both categories.

4. Failed Emissions Test

If the exhaust leak is after the catalytic converter, there’s really no reason the vehicle should fail an emissions test. However, if the exhaust leak is before the catalytic converter, your vehicle absolutely should not pass an emissions test.

This is straight exhaust pumping itself into the atmosphere before it goes through the catalytic converter, which helps reduce the number of harmful emissions.

Finally, while we focused on emissions here, an exhaust leak also might lead to your vehicle failing a decibel reading depending on where you live. Exhaust leaks tend to be loud, and if you live in an area with a maximum decibel reading exhaust leaks can put your vehicle over the top.

What Causes Exhaust Leaks?

Exhaust systems use metal components throughout, and with enough time and the right conditions, metal will rust. If you leave the exhaust alone long enough with active rust, it’ll eat through all the metal. This creates a hole where the exhaust can escape.

If you live in an area that frequently salts roads or near the ocean where there’s lots of salt in the air it can cause rust to form faster.

Preventing Exhaust Leaks

It’s better to avoid a problem in the first place instead of trying to deal with it after the fact, and exhaust leaks are no exception. The key to preventing exhaust leaks is to prevent rust. There are a few different products you can spray on the exhaust to form a barrier between the metal and any moisture in the air to keep rust away.

But these protections only last so long, so you’ll need to reapply them according to the product directions to keep rust away year after year. Whether you decide to use one of these products or not, you should inspect your vehicle’s exhaust components about once a year to check for rust.

If you notice any rust forming, you should treat the affected area right away to keep it from eating through too much metal. You can either sand the rust off and then use one of the products we highlighted above, or there are products you can spray directly onto the rust to treat and cover it at the same time!

The choice is up to you, but if you follow the steps we highlighted above you shouldn’t have to worry about rust eating through any of your exhaust components.

Finding Exhaust Leaks

Whether you’re trying to figure out if your vehicle has an exhaust leak or if you’re trying to pinpoint exactly where it’s at, there are a few tips you can use to make it much easier to figure it all out.

The first thing you want to do when you’re trying to find an exhaust leak is to get a partner to help you out. Next, find a way to elevate your vehicle. You need to be able to visually inspect the entire exhaust system, and if you can’t access it then you won’t be able to do this effectively!

Once you can access the exhaust system and have your partner, find a way for one person to cover up the tailpipe. Something like a piece of cardboard or a clipboard works great for this.

Once you cover up the exhaust you need to listen. If there’s an exhaust leak you should hear a hissing sound coming from a section of the exhaust as the extra exhaust pressure pushes its way out. Using this method you can usually quickly and easily determine if your vehicle has an exhaust leak and exactly where it is.

How To Fix Exhaust Leaks

If your vehicle has an exhaust leak you need to fix it. Not only is it bad for the environment and potentially bad for your vehicle, but in most states, you can’t pass an inspection with an exhaust leak! But how exactly do you go about fixing an exhaust leak?

Well, you’ll either need to weld another piece of metal over the rusted-out component or you’ll need to replace the component entirely. The best option for your vehicle all depends on the size of the leak and the overall condition of the rest of the part.

Exhaust Leak Repair Cost

So now you might be wondering how much an exhaust leak repair costs. Well, you don’t want to spend a ton of money welding a new piece of metal on it only to have another section fail in a few weeks or months! You can typically have a professional repair shop repair smaller leaks for $100 to $300, while all-new exhaust pipes can run between $800 and $1,000.

Meanwhile, if the catalytic converter rusts through, you can expect to spend between $1,700 and $2,500 for a new one. If you can repair it with a little welding and extra metal, that’s clearly the way to go.

If you have the welder, the experience, and the materials you can complete this job for yourself too. Even better, if you’re completing the work yourself all you need to pay for is the materials. Since these are generally relatively low cost, if you can weld the new pieces on yourself you can get the job done for $20 to $50.

Final Thoughts

Nobody wants to deal with an exhaust leak, but now that you know a little more about them, you can take a few steps to keep them from happening in the first place. They’re usually extremely preventable, and if you catch them early you typically don’t need to spend a ton to fix them.

So, take the time to inspect your exhaust system, and then keep an ear out for any potential issues down the road. These little steps might save you a ton of money and frustration in the future!

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Rickard Cefalk

Rickard is the owner of Caraspect.com and a dedicated and avid do-it-yourselfer who has always enjoyed working on his own vehicles since childhood. He now devotes his time to sharing his expert knowledge of car maintenance and other car-related information through his website.

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