I have a 2003 TJ with a 4.0 that I have been fighting an exhaust leak on for 6000 miles. The muffler was shot so I replaced it with a Flowmaster cat back. It is leaking around the collector at the manifold. I have taken the exhaust completely off and cleaned it with a wire wheel and bought new bolt and c-nuts and put it back together and still no good. I even pulled it back off and put a bead of copper high heat silicone around the inside of the collector and it was good for a couple of weeks and then started leaking again. The cats are not factory, they had a 2017 on the heat shield on them and looked really good when I looked down in them. I am open to suggestions at this point. I did the whole shop vac in the back of the exhaust and squirted soapy water on it and is for sure leaking at those collectors. I know those are supposed to just be metal on metal but do they make some sort of collector gasket I could make work to seal it up. You can see in that top pic it doesn't even look like the header is making contact hardly anywhere on the collector.
I need some ideas for an exhaust leak
- Thread starter thekevin
- Start date
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The bolts may have been overtightened to try and stop a leak for another reason but flattening those may fix the whole thing.
The nuts you plan on using are total mickey mouse for an exhaust connection, get some decent hardware.
How would I go about straightening those out. A torch and a couple of pair of vice grips.
You could use a torch but you'll want to make sure you don't accidentally cut into the pipe.
Vise grips are good for a lot of things but getting maximum leverage isn't one of them.
If you have two large crescent wrenches the long handles may give you enough leverage that the torch isn't needed. I have a 15 inch and an 18 inch but if you don't maybe a couple 8 inchers with some pipe added may do the trick. No matter what you use it's probably best to have a helper.
Another way that may work. Flip the whole thing over and have one of you two hold it that way while the other one sets the "pointy" ends on two blocks of some kind and hits the thinner bowed part with a heavy hammer. This won't be too easy because the converters are kinda in the way but maybe a large punch would help.
Someone may have better ideas, those are just what I see that would irritate my wife when I asked her to help.
After all that, it looks like those pipes have a very deep tapered end. You probably want to make sure they touch the tapered end of the manifold and not the big flat flange part before tightening them up. If they touch the flange first some trimming would be in order.
Vise grips are good for a lot of things but getting maximum leverage isn't one of them.
If you have two large crescent wrenches the long handles may give you enough leverage that the torch isn't needed. I have a 15 inch and an 18 inch but if you don't maybe a couple 8 inchers with some pipe added may do the trick. No matter what you use it's probably best to have a helper.
Another way that may work. Flip the whole thing over and have one of you two hold it that way while the other one sets the "pointy" ends on two blocks of some kind and hits the thinner bowed part with a heavy hammer. This won't be too easy because the converters are kinda in the way but maybe a large punch would help.
Someone may have better ideas, those are just what I see that would irritate my wife when I asked her to help.
After all that, it looks like those pipes have a very deep tapered end. You probably want to make sure they touch the tapered end of the manifold and not the big flat flange part before tightening them up. If they touch the flange first some trimming would be in order.
Are you sure those don't take a doughnut gasket? Metal on metal doesn't sound right for a air tight seal.
I am like 90% sure they don't. You can see the pic of the exhaust above and here is what the manifold looks like. I found these tiny copper exhaust gaskets that are for a samurai that I may buy and adjust to fit and sandwich in there.
You can always go this route, which is what I will ultimately do on the entire system.
VBand Clamp and flange joints
VBand Clamp and flange joints
I have used similar ones on turbo exhaust applications. Reusable and virtually 100% leak free(welds need to be really good)
Cheap investment if you are looking at a clean serviceable exhaust system.
Cheap investment if you are looking at a clean serviceable exhaust system.
