How To Fix An Exhaust Leak On Flange: Effortless Way

The combustion chamber of your car generates a lot of gas. The primary objective of exhaust system is to direct this gas from the chamber to the outside. The whole process may sound like an easy task, but it’s a lengthy and complicated mechanism.

Your exhaust system is attached to the engine through exhaust flange. They also need a gasket between the engine and the header. You’ll find 2 or 3 bolts to tighten the flange on the exhaust system.

Now, a leak in the flange will cause severe issues. It will leak harmful fumes that have carbon monoxide. Other than that, your engine will have to work harder, which will decrease fuel efficiency. 

So, you shouldn’t drive a car with an exhaust leak in the flange. Lucky for you, we’re here to talk all about how to fix an exhaust leak on flange, including how much it would cost.

How To Fix An Exhaust Leak On Flange

How to Know You Have an Exhaust Leak on Flange:

If there’s a leak on the flange, there’ll be several signs that you can identify. Some of them could be-

Loud Noise

Your engine may create unusually loud noises that you didn’t hear before. You may also hear a tapping or hissing sound in the system. It will increase as you push down the accelerator.

Less Fuel Efficiency

Your engine will perform poorly than before in terms of fuel efficiency. A leak in the flange will require the engine to work harder than before. It will have to use more fuel which eventually will lead to less fuel efficiency.

Smell of Burning

If you have any debris stuck in the flange, it will start to burn in case you have an exhaust leak there. If the debris is made of plastic, you’ll be able to smell it. You can also find fumes coming out of the place.

Lowered Exhaust Pipe

If the exhaust pipe seems to be lower than before, you definitely have a broken gasket or flange. It’s dangerous for you and other vehicles as well. So, the moment you identify it, run to a mechanic to get it fixed.

Smell of Gas

If you have an exhaust leak on the flange, fumes will start to leak, which you eventually can smell. So, if you start to smell gas that you didn’t before while driving, check the system for an exhaust leak.

How to Identify the Exhaust Leak on Flange:

To fix the leak, you first have to identify it. The leak could be at the flange or anywhere else from the engine to the exhaust system. So, let’s see how you can locate exhaust leaks on your car’s system.

You have to inspect the manifold of the exhaust system first. To find it, you have to find where the gas leaves the engine. You’ll find a couple of tubes or a large one that may seem rusty. A heat shield might also be covering the tube.

Next, follow the tube towards the end of the exhaust pipe. Try to find small holes or cracks while you inspect. All of the surrounding tubes are integral components that you also should inspect for cracks.

If you can’t find anything with the naked eye, turn on the engine and try to see if any smoke comes out from anywhere. If your exhaust flange has any leak, you’ll find smoke coming out of there, where you may find a cracked gasket.

Things Required To Fix Exhaust Leak:

Fixing an exhaust leak on a flange is a complicated process if you don’t know how to do it. It’s always recommended to visit a mechanic in such cases. 

However, if you have quite a bit of knowledge about cars, you can do it yourself by following our instructions.


Fixing the exhaust leak of the flange in a dealership will cost you around $300-$400. If you need any additional parts, add the cost to that as well. 

If you do it by yourself at home, you’ll just need your toolbox. You might need to replace the gasket if it can’t be fixed, but it won’t cost you more than $30-$40.


The whole process will take 2-3 hours, depending on your expertise. It may also take more time if the leak is hard to identify.


  • Deep sockets
  • Wrenches
  • Scraper
  • Steel brush
  • New gasket
  • Exhaust tape

How To Fix An Exhaust Leak On Flange – Easy Steps

Now, if there’s a small hole in the flange, you can just fix it instead of replacing the flange. Let’s see how you can do it.

  1. After you find the hole, turn off the engine and let the system cool down.
  2. Clean the flange with a steel brush properly. There might be some debris coming out of the flange, so you should wear glass to protect your eyes.
  3. Scrape the area of the flange that needs repairing with a scraper.
  4. Clean the same place with some acetone.
  5. Put some exhaust tape in the hole or crack as much as you need.

This process should fix the issue if you have a small hole or crack in the flange. In case of a broken gasket, you have to replace the flange. While we’re at it, let’s cover replacing the exhaust flange as well.

How to Replace Exhaust Flange:

As we already mentioned, replacing a flange is costly at a mechanic shop. If you do it yourself, just buy the parts and use your tools. Follow our steps adequately explained from here:

  1. You have to find the bolts in the flange and remove them first. But, keep two bolts in the system that is on both sides.
  2. If the flange is stuck, use a scraper to clean all the debris from the gasket and flange. Use a flat metal or even a knife to pry off the flange.
  3. Carefully remove all the gaskets and the flange. Clean the place again with a scraper.
  4. Place the new flange and the gasket. Make sure that they fit correctly. Otherwise, you’ll end up having exhaust leaks again.
  5. When the flange is placed correctly, put the bolts in place and tighten with a wrench.

Frequently Asked Questions

How much would it cost to replace the gasket?

If your exhaust flange is alright, but the gasket is cracked, you can replace it only. A gasket will cost you $35-$40.

Can I drive with an exhaust leak in the flange?

You can, but you absolutely should not! Not only will it reduce fuel efficiency, but you’ll also increase the chances of letting harmful fumes enter the car. Your engine will perform poorly, which will lead to a bad driving experience.

Will I be able to smell any fume if the exhaust has any leaks?

You may smell something like sulfur if you have a leak in your exhaust flange. Of course, you have to know what sulfur smells like to identify it. But, there are plenty of other ways to identify exhaust leaks, which we covered earlier.


Driving with an exhaust leak is extremely dangerous. If you keep doing it for a long time, the engine will create a loud noise, and anyone can identify it. You may end up getting a ticket if a law enforcer identifies it.

Other than that, driving with exhaust leak will eventually increase your fuel cost. The money you’ll spend on fuel will ultimately be more than the money you’d spend to fix the exhaust leak.

 So, follow our guide on how to fix an exhaust leak on flange and drive safely!

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