1A Auto Video Library
Our how-to videos have helped repair over 100 million vehicles.

Loud Exhaust Smells How to Find Exhaust Leaks in Your Car or Truck

Created on: 2020-07-23

This video shows you how to find exhaust leaks on your vehicle.

That exhaust is pretty loud. We're gonna have to check that out. Hey, friends, it's Len from 1A Auto. Today I want to talk to you about exhaust leaks. This one right here has an exhaust leak and we wanna try to figure out where it is. There's gonna be several places to look, of course they're all gonna be on the exhaust system, so it's gonna be underneath the vehicle. Something that I wanted to quickly talk about is that if you're gonna be checking out your vehicle inside of an enclosed area, such as maybe a garage, or a studio, or a bay like we are in, of course you're gonna wanna make sure it's well ventilated because as your vehicle's running, the exhaust is expelling carbon dioxide. Looking at the exhaust, which you can tell runs down the entire aspect of the vehicle generally from the motor all the way to the rear of the vehicle on almost all vehicles. You're gonna notice the pipe comes down and it's gonna have several different pieces and they're all gonna look a little bit different. If you were to look up closest to the engine, you're gonna see where the manifold is.

Usually if there was a leak that had to do with the manifold, it'd either be because there's a crack on the manifold, or because the gasket in between the manifold and the engine itself is more than likely no good in some way. Otherwise, if you were to follow it down, you should see a flex pipe. The flex pipe is a pipe that should make it so your exhaust can move around. And that's good because, as you're revving your engine, or you're driving or reversing or whatever the case may be, the engine is gonna be shifting around, so it needs to have a flexible joint. The flex pipe is a very common area for most exhaust leaks. It's not the only area, so I'm gonna continue on. We'll just go over a couple of the different areas and then of course we'll start the vehicle and we'll check it at that point. You have your flex pipe and then we're gonna have our catalytic converter. The catalytic converter's gonna have a gasket right in between that and the flex pipe, that's fairly common for the flanges and whatnot to rot out and then of course you'll have a leak.

More than likely you're gonna have a mid-pipe that goes between your catalytic converter and your muffler. The mid-pipe might have something that looks like this, which is kind of like a secondary muffler of some sort. And more than likely they tend to rot out all along the edges. If you were to see something that looks like this, that doesn't necessarily mean that there's a leak there. There could be of course, and I'll show you how to check it in a minute. But this actually has several areas or different shells. There's an exterior shell and an interior shell and this is just the exterior. So, if you see some stuff that looks like that, I wouldn't necessarily condemn it right off the bat. Almost every vehicle is gonna have a different type of muffler and this is just the one on this vehicle that we're working on. But you should have an inlet area where the mid-pipe goes into it, and then you should have an exporting area or a tailpipe area that goes out, and of course it would lead out to the rear of the bumper.

Now, when we're checking our exhaust system, it's important to remember that you're not necessarily just looking for a large gaping hole in the exhaust system, or even an area where there might be an issue with the gasket. You also wanna look around see if you can find any black soot. The reason why you might have black soot is because, like I said, if you have an exhaust leak, it's gonna be expelling that carbon dioxide and of course there's gonna be other contaminants as well. So, now that we've just given it a good visual check, we also wanna give it an audible check. So, what we need to do is start up the vehicle and get back under here. Something that's important to remember is once the vehicle is running, the exhaust is gonna get hot, so we're not gonna try to touch it. When I say that we're gonna put our hands near it to try to feel if there's an air coming out, I mean just near it, you definitely don't wanna burn yourself, safety first. Okay, so I started it up and I'm back underneath the vehicle.

As you can tell, it's pretty loud pretty much right where I'm standing, so I know about where to start. But I also need to check the rest of the exhaust, I never like to stop at just the first thing that I find. I'm gonna start up towards the front. If I feel around up towards here, I don't feel any air coming around. I'm coming down now and I'm around the flex pipe. The flex pipe is a very common area for these to leak but in all honesty, this one doesn't feel too bad at all. I'm gonna keep working my way this way, and right here actually is where I feel the exhaust leak on this particular vehicle. Yeah, right along here. So I'm gonna keep moving. I'm gonna feel up along the top of this and along the sides, I can see all these areas that look like they're gonna be a problem. But in all honesty, I don't feel any air coming out of those. So, those really aren't very worrisome for me at all. I'm gonna come down along this area feeling all the way around. I'm not touching the pipe because, like I said, it's gonna get hot, I'm just feeling for air.

I don't feel anything down along this way, up along the top of the muffler, nothing. Along the sides, and of course along the back seam, nothing. And then, of course, we've got our tailpipe, you always wanna check everything, that feels good. The next thing I wanna do is just take a gloved hand, and you need to have a gloved hand, and I'm just gonna cover the exhaust like this. This should start holding pressure and it should wanna blow my hand off. I don't feel any pressure right there. If I do, it's minimal. That tells me that there's definitely an exhaust leak. The best way to check this now is if you were to have a second person to hold this like this, and then of course you'd wanna check the whole exhaust the same way I just showed you a second ago. So, now, if you're having a hard time finding the exhaust leak that way, but you can definitely hear it, and you knew which approximate area it was in, you could try using a mirror. You'd wanna do that while the vehicle is running. And the reason for that is because if you brought your mirror up and around the exhaust pipe in the areas that you thought that the exhaust leak might be. As soon as the mirror got over the leak, you'd see the mirror start to steam up a little bit, and of course, that's gonna be a telltale sign of the fact that there's a leak there.

So, now let's say that you found your exhaust leak. Well, that's great, good for you. What you have to think about though, is the parts that you're gonna have to replace at this point. Because we found our exhaust leak here, that's actually part of the catalytic converter, which tells me that from this plant right here, at the flex pipe, I'm gonna have to replace going in this direction. You're gonna wanna look at the other parts that are in that direction though. Because if you have a mid-pipe that has one of these pieces on it right here, and it looks like it's in poor condition, maybe it's rotting, and there's areas that looks like it's gonna be an issue in the near future. Do you think it's probably a good idea to leave it on there and just replace the one part that you thought was bad? Or do you think it's probably a good idea to just go ahead and replace the unit as a whole going back? You have to make your own determination on that because yours might look better than mine.

So, I don't wanna tell you to go ahead and replace it. But for me, on this particular vehicle, I would of course replace the unit that I found was an issue. I would analyze the rest of it and, like I said, on this vehicle, unfortunately, I would just have to replace the whole bit. Okay, friends, so we tried to show you a couple of places to look for on your exhaust to look for an exhaust leak. Hopefully you found one. One thing to think about, if you did find an exhaust leak, you need to fix it ASAP. The reason why I say that you need to fix it ASAP is because, like I said before, your car produces carbon dioxide. The reason why your tailpipe goes out towards the rear of your vehicle is to make sure that it expels out and as far away from the passengers as possible. If you have an exhaust leak in the front, or even in the middle, there's a possibility that exhaust could be going up. Maybe coming in those windows if you're driving around with your windows down, or even if you had for some reason a hole inside your floorboard or even in your firewall. So, fix that exhaust leak ASAP.

With all that said, I hope you enjoyed the video. If you did make sure you smash the like button for me, it would mean the world. If you got something to say, please leave it in the comment section below because I always love to hear from you. While you're at it, why don't you go ahead and subscribe and ring the bell, that way that you can be kept up with all of our latest content. Thanks.

Thanks for watching. Visit 1aauto.com for quality auto parts shipped to your door, the place for DIY auto repair. And if you enjoyed this video, please click the subscribe button.

How to Replace Flex Pipe 2006-12 Nissan Altima

Watch this video to learn how to remove and replace the exhaust flex pipe on your 06-14 Nissan Altima. 1A Auto shows you how to do it yourself!

Share on:
Go To Top

Same Day Shipping

Need your part faster? Choose expedited shipping at checkout.

Guaranteed To Fit

Highest quality, direct fit replacement auto parts enforced to the strictest product standards.

USA Customer Support

Exceeding customers' expectations, our team of passionate auto enthusiasts are here to help.

Instructional Video Library

Thousands of how-to auto repair videos to guide you step-by-step through your repair.