How to Replace Flex Pipe 2010-14 Hyundai Sonata

Hey, friends. It's Len here at 1A Auto. Today, we're working on a 2011 Hyundai Sonata. We're going to be doing an easy job, a flex pipe. This particular pipe has California emissions, so it has the bung right here for the O2 sensor. Very important to make sure that you have that if you're working on this vehicle and it has California emissions. If you need this part or any other part, you can always check us out at 1aauto.com.

Okay, everyone. So, here we go. We're underneath our vehicle. We've got our flex pipe here, which is what we're going to be replacing. It's the part with the mesh on it, right. We've got our O2 sensor right up here. This is very delicate. It has wiring that goes up. It's a super long wire, goes all the way up there. You can connect it from up there if you wanted to. I wanted to show you that there's four nuts. There's one right here. There's one located on the other side of the pipe, right over there. There's one right here, one right there, and then this is our hangar. Okay. So, it's going to be very simple to get out of here. The hardest part is just when things are rusted up like this, you might have to use a little bit of heat. Heat it up, see if you can get it to worked out or to work out.

So, what I'm going to do first is I'm going to spray everything down with a little bit of penetrant, and then I'm going to go ahead and I'm going to remove this O2 sensor. Then I'll go ahead and start getting ready to unbolt these. With the O2 sensor, you just want to try to spray at the pipe, basically. You don't need to spray the whole sensor all the way up by the wires and all that stuff. Just pretty much where it connects in with the pipe, that's the important part to spray. The nuts, we'll spray those, right along where it connects in with the stud. We're going to watch our eyes on this one. There we go.

Now, we can grab our O2 sensor socket. That looks something like this, okay. It's got a slot out of it and that's great because we need to get it over the wires that are on the O2 sensor, and then down onto the stud of the O2 sensor, and then we're going to turn it and break it free. Like I mentioned, it's completely up to you if you want to disconnect the O2 sensor up at the top. This O2 sensor wire is probably like maybe this long. So, it's plenty long. Okay. If it was a short wire, you definitely want to disconnect the connector. So, when I'm turning this socket right here and I'm turning out the O2 sensor to get it from up out of the pipe, I'm going to be twisting those wires. Twist, twist, twist, right? If the wires are only this long and I'm twisting them, they're going to get super tight, possibly break. Like I said, it's super sensitive material. So, with this wire being this long, I'm really not as worried about getting a couple of little twists in it. I don't even think the wire's going to know what's happening.

So, I'm going to grab my safety glasses. Super important. I've got my O2 sensor socket, my ratchet, and I might even need a short extension. We'll see. I'm just going to put my socket up on there, hopefully. See if I can get my hand in. Next, we're going to try to get our ratchet up in there. It's just a 3/8 ratchet. Your socket might be a different size. Just... You know what size your socket is, so use the correct ratchet. Let me see if I can't get it up in there now. My ratchet facing the right way, and turn this to the left to get it off. If I can turn... Okay. Super tight. So, that's no big deal. All I'm going to do is I'm going to remove my ratchet and my socket, and I'm going to heat it up gently at the pipe. I don't want to go very hot because I don't want to damage the sensor or the wiring. Also, if you go super hot, you could mess up the threads on the sensor itself, in which case you're going to have to replace the sensor, and they can get pretty costly. So, just use your best judgment. You can use something as simple as this, little butane torch. Okay. I don't really think a cigarette lighter or anything like that's probably going to work, but whatever you happen to have, you just need a little bit of heat.

Sometimes, penetrant can be flammable. So, you need to make sure you have something available to make sure you put out a fire. Let's see. I'm going to test it on this one. Not too bad. Doesn't look like it's going to combust on me or anything like that, but it is going to smoke, so you need to think about that. Might be a good idea to have your hood up. So, that way there, when the smoke comes out, it's going to go straight up and not just keep bellowing down into your face. Try not to breathe in the smoke. I don't probably need to tell you that.

I'm just going to get this up in there. Gonna get this up here. I'm just going to try doing it with the socket right on the ratchet already. See if I can work it's way on there. Let's see. They don't give you much room to work in here, of course. So, that's always nice of them. Let's do something a little different. Now that we've got that heated up, I'm just going to spray this just like that. We'll let it sit again. All right. Now, what we can do is we'll just go up top. We'll disconnect that wire and that way there, when we remove those four nuts and this right here, we can carefully take out the whole pipe and hopefully, we'll be able to get better angle at that to be able to pull it out. It would have been nice just like this to get it done easy peasy, but we'll just have to take an extra step and we'll do it the other way, okay?

Okay. So, I just came up top. I got a pretty clear view of everything from up here. So, I'm just going to grab my same O2 sensor socket and my ratchet and I'm going to try to come from up here, turn it to the left and break it free. Yeah. There we go. It came free. So, I'm going to turn the O2 sensor, try to turn it out of the pipe, and I'll show you what that looks like. I'll show you what to look for on it to make sure that nothing was damaged. Something that commonly goes bad with these, if they're stuck in your pipe like that was, is the threads. It might be hard to see with the camera, but I'm sure you know what threading looks like. It's the same as on any bolt or whatever you might have. If the threads look like they're munged or missing, essentially, just from being wiped out because they were stuck in the pipe and they just kind of became worn over time and rotted out, you want to replace this O2 sensor. This one right here looks like it's in great condition. You can also take a look at the wires. They look great. So, this sensor right here is reusable. There's nothing wrong with it in any way. So, strange to say, but I guess we got lucky.

Now, we're clear to go back underneath. We'll remove those four nuts that I showed you and we'll get the pipe out of there. So, I've got a 17 millimeter and I've just got a little extension here. All I'm going to do is I'm going to try to put it on here. It doesn't really fit on very well 'cause everything's rotted. So, I'm just going to take my hammer and I'll be careful not to pinch myself or hurt myself, of course. Safety first. I'm just going to try to hammer it on. I got my safety glasses on. There's a lot of rust falling down. I want to see my kids and my grandkids and their kids some day. So, I've got that on there. So, I know that one's pretty much cleaned up. Banging around a little bit. If you wanted to, you can go ahead and take that off now. For me, personally, what I'm going to do right now though is I'm just going to make sure that all the nuts are ready to come off. So, I got that on there. I'll just work it around. Being careful not to stretch it too much because I do need to have pretty good grip. I'm just going to wiggle it all around, do the same thing the other one.

So, I just took my 19 millimeter socket with a little swivel and my long extension. I'm just putting it on those nuts, making sure that I will be able to get them off when it comes time. They feel pretty great, so that's nice. Very cool. Okay. So, judging by the look of these nuts in the studs right here, they're probably going to need a little bit of heat. Okay. So, we're just going to use our little butane torch or torched, whatever you have access to. Heat up the nut. You don't need to heat up the stud so much as the nut, okay. Heat that up. If you want to try to get it nice and red, that's up to you. But basically, we need to turn this to the left and remove it.

Now, I'm going to try to get my 17 back on there. Let's try it without the ratchet first. Get it on as far as you can so you have less chances of stripping it out or rounding it out. Just got a long half-inch ratchet. Let's see if I can't break it free. Turn it the other way. You can just rock it back and forth. Just be careful when you're going. You don't want to be banging your O2 sensor over here up against your body, the sub-frame here. I guess it's just... Really, it's just the body. Sounds like it's getting ready to break. So, we need to think about something. If we're going to be replacing this, which we are, we've got brand new studs here. Okay. So, that's nice. If we break the studs, whatever. But are we going to have the nuts to be able to put this on once we're done breaking this if it breaks? If you don't, well, you can go ahead and use some penetrant and work it back and forth and just hope that that nut comes completely off so you can reuse it, or if you happen to have a nut that'll work, that's great for you. All right. So, I'm just going to check to see if I have a nut. In case it breaks, I don't want to worry about it.

So, I'm just going to work on taking this out. Like I said, the stud sounds like it's going to break. So, you're going to want to make sure that you have an extra set of nuts and they need to be locking nuts. If you don't have locking nuts, you can try to use something like Threadlocker. Problem is this exhaust gets hot, it's going to heat up your Threadlocker and it might not hold like it should. So, if you break the studs, you're not probably going to be able to get the nut off the stud once it's broken. So, you're going to need nuts, okay? If you have time and you want to just keep on working this back and forth with some penetrant, you can go ahead and do that. Tighten it, loosen it. Tighten it. This is just going to help work the penetrant in. Seems like we got a little further that time. Just keep working it back and forth. Depends on how much time you have. Okay.

Once I get this off, I'm just going to do the same exact thing to the other side. So, as you can see, the nut's coming off. It's almost all the way off. There's our problem child. Okay. Save it, replace it. You do you, booboo. Now, once I get this loose... There we go. There is a possibility that our catalytic converter pipe might come down and hurt us and/or put a tug on this wiring right hee. So, what I'm going to do is I'm just going to let it hang, okay. That way there, in case this pipe comes down, which it really shouldn't because if you follow it back, you got this rubber right here. Okay. So, that's going to make it so it really can't come down too far, but who knows. I don't want to put a tug on this and I also don't want this to come down, smack me in the face, get rust of my beard, anything like that.

So, we can go ahead and separate this if we want. We've got our gasket in there. We're going to replace this gasket. You never reuse gaskets, okay. So, if you get the pipe, just make sure you get the gaskets. So, that's good like that for now. Now, we're going to move up to the 19 millimeters up there. If you have a swivel head socket, that might be wonderful, or if you just have a swivel with an extension, you can go with that as well. But basically, it's a 19, turn it to the left, get it out. Okay.

19, nut. Let's do the other one. Freeing up my pipe at this point because now it's pretty much free to come out, in exception of this right here. All right. So, it's up to you how you want to take this off, but essentially this metal piece has to come out of this rubber. All right. You can try to take it off this side and then later on, get it apart. Whichever way works best for you. To me, it works best just to push the whole thing right off. Okay. Now, we're just going to try to get the pipe out. So, whichever way makes it so it comes off for you, do it that way. There's our gasket. We're going to make sure we recycle that. It's quality junk. And here's our pipe that we're replacing. As you can tell, not so good. That's why we're going to replace this with a quality 1A Auto part.

Here we are, friends. I have a quick product comparison for you. We have our original quality Hyundai Sonata 2011 flex pipe right here, and we have our brand new quality 1A Auto part right here. I just want to compare them both next to each other for you so you can see that they are the exact same, in exception of... Well, this one's old and going to go in the recycling bin, and this one's brand new. Okay. But let's just double check everything and make sure what we're dealing with is right. We've got our flange. Both flanges look good. The old has two mounting bolts. The new has two mounting bolts. We've got our little hanger. Old one has a hanger. They both line up perfect. If this one was facing off over this way or vice versa, we got ourselves a problem, but it looks perfect. So, we'll move along. I'm going to turn it for you. There we are.

We've got our other side flange. As you can tell, they're both the exact same. So, that's wonderful. Lastly, what we need to make sure is that we have the California emissions, I guess, 02 sensor hole. So, as you can tell, it's right here. Came with one. This one has one. This one needs to have it too. If you got one of these pipes and it doesn't have this, then you probably got one that has the federal emissions. You need to have the California emissions if you have this in your flex pipe, okay? So, as you can tell, this part right here is a quality part. So, if you need this part or any other part, you can always check us out at 1aauto.com. Thanks.

All right. So, up on the manifold pipe up there, there's another one of these gaskets. This one came from off this side. All right. But there is one up there. So, what you want to do is you just want to get it off however you need to do it. Make sure you're wearing safety glasses in case rust starts flaking off and tries to come at you. Now, pull it off. I'll show you it in one second here. There it is. Okay. We're going to replace it. So, I'm going to make sure I recycle it properly. Next, what you'll notice is there's a lot of rust and crud all over this thing. This is going to get in between your brand new gasket and your pipe, and it's going to cause an exhaust leak. So, you're going to think that we really didn't do a good fix. So, what we want to do is we want to make sure we get off as much of this stuff as possible, clean it up as clean as possible and smooth as possible. You can scrape it, you can sand it, you can do whatever you want to do. Needs to be as clean as possible where the gasket's going to ride, to put it simply.

Now, we're going to do the same thing on this one. We're going to come around from the backside or the front side, I guess, aiming this way. We're going to try to clean this all up as well as possible as well. Okay. Try to make it so it's nice and clean shiny metal if you can, and then we'll go ahead and put in our new pipe. So, as you can tell, I cleaned up where the seals going to be riding. I just used the little scuffing disk and I got it as good as possible. I did up there, and then I did the pipe right back here. So, I got that done as good as possible. Doesn't have to be perfect. It is what it is, and I tried. Best-effort, okay? So, now let's get our pipe up there with our gaskets, and then we'll get in on tightening everything up.

So, let's say you get your brand new gasket, right. It's beautiful. You can't wait to install this with your brand new pipe. You go to put it up on there and the bolt holes don't line up. You've got a bolt whole here and then this one, it's not even close. Right. What are we going to do? Well, we're going to return this one, get our money back. When we go, we'll make sure we say, "Thank you very much." We're just going to take our old one and we'll clean it up. You can use sandpaper or a brush or whatever. Just try to get off as much of the crud as you can so it's nice and smooth on both sides. Okay. And we're just going to go ahead and reuse it. It is the right thing to do? I'd rather replace it, but is it the best that we can do since our car is kind of downed right now? We can't go driving it with the exhaust hanging down like this. that's what we're going to do.

So, I'll get that one up on there. Okay. I've got my pipe and put my little rubber on here. It's going to go on there. That's the mounting rubber, right. So, this is just going to go up in there. Basically, when it goes in, it's going to sit like this because we've got our O2 sensor bung. That's going to go facing up because that's where we took the O2 sensor out of. This is going to go down because that's where that mounts onto, and off we go or on we go, I guess. Just weasel it up in there however you need to do it, okay. To me, it was easier to get it off this pipe first. Well, off that pipe first and then off this pipe. So, I'm going to go on this pipe first, then on that pipe. So, I'm going to grab my gasket. Not that brand new one, but the one that I cleaned up. I'm just going to try to get it on there. See if I can do it. Everything likes to put up a fight on the videos. So, that's always fun, but it's all right.

Line up the studs with the holes. Get it in. Got our gasket up on there. So, we're going to line up those studs with he holes. Give it a little twist if we need to. Okay. Everything's situated in there now. So, that looks good. Now, we're going to go ahead and we're going to put in our nuts. We're going to tighten those up and we'll get this on here and our O2 sensor. So, I've got my 19 millimeter socket up there. I'm just going to tighten these bolts up. All right. I'm using a pretty long ratchet here. So, I'm just going to go up a little higher like that. Pretty much just snug and then a little more. I don't want to go ahead and break those studs. Okay. We're going to do the same thing for the lower one and then I'm going to come over here and I'm going to tighten up these 17s. Then, we'll go ahead and put this on. We'll get everything back to being situated and we'll go back up top, and we'll put in that O2 sensor.

So, I'm just to go ahead and tighten these up, being careful not to break the studs just like on top, right. I'm turning it to the right with my 17 millimeter socket. All right. So, now we're just going to tighten up these lower ones with our 17 millimeter socket. Just going to bottom it, give it a little bit more. I don't want to break either of the studs. So, I'm going to get this off. I'm going to do the same thing to the other one. We'll get this on.

Okay. So, now we're going to get ready to put on this little mount right here. It'll be a little easier to get on if you just put on whatever you might have for grease. Okay. It doesn't have to be anything special. All we want it to do is give us some lubrication. Let's see if I can get it on there. Easy peasy. Love it. Now, we're going to hang this again. That looks pretty great. We'll just take our flashlight. We'll double-check to make sure we tightened everything. One, two, definitely done. Those up there, definitely done. Get this all run, get this on here. Okay. Now we can bring the vehicle down and we'll go and try to tighten up that upper O2 sensor there, and we'll move along.

So, I've got my O2 sensor right here. We already checked it. We made sure that it's nice and pretty. It looks good. The wires are fine, threads are great. I'm going to bring it back down under here and I'm going to hand tighten it into the sensor bung, which is just the port on the pipe. I guess the word for it or the term for it is bung, so that's why I said it, just so you know. I'm not a weirdo. So, I'm going to go left a little bit first because when I turn this to the right, it's going to be twisting those wires to the right. So, I just kind of made a guesstimate of approximately how many times I'm going to have to turn this to the right, and I went that many times to the left. So, hopefully by the time I'm done tightening this, the wire will be pretty straight. Come on, baby. There we go. Looks pretty good. I'm just going to put it into all it's little clips now real quick. You want to make sure that it's secured where it's supposed to be, of course.

Okay. Now, I'm going to go ahead and tighten it up. I've got my O2 sensor socket, my ratchet on here. The hardest part's going to be getting it on and then once I do, I'm just going to tighten it up. Easy peasy. I don't want to go too tight and strip it, but you also need to make sure that you don't go too loose and it vibrates up. So, you're just going to have to use your best judgment. There is no torque spec available that I found. So, I'm going to go with... Click. It's torqued. Just double check. Make sure we got that secured so it's not hanging down. We don't want to go on a pipe or anywhere. We didn't disconnect it from up here. If we did, we'd want to make sure that we did reconnect it. We did not, so I'm not worried about it. Also make sure I got all my tools out of here and then we'll go ahead and spark up the vehicle and we'll make sure that there's no check engine light on.

Okay, friends. Here we go. Turn the key. There's where our check engine light's going to be. So, we know where it is to watch for. So, we can leave it running for a minute, but I'm indoors. So, I don't want to run it in the indoors for very long, asphyxiate myself or anything. I'm listening. I don't hear any major exhaust leaks. On some vehicles, you can go out back and you can try to plug the tailpipe if you're wearing a glove of some sort or you can just put a couple of rags. This particular one has... Let's turn that off. Has a little cover on it. So, even though I try to plug it, it's really not going to block the exhaust to see if there's back pressure. So, there really is no test for that, but basically just listen. If it still sounds like it's going... It's probably not so great, okay? This one sounds good. We did a good job. Great job, everybody.

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