Muffler Heat

Zukey14

TJ Enthusiast
Joined
Dec 6, 2018
Messages
116
Location
Lambertville Michigan
I am having an issue where my rear passenger floor pan is getting hot enough to melt the floor mat and the rear drain plugs. I found this because I was removing the mats and cleaning the interior to install Bedrug. I dont have carpet now and there is no heat shield on the muffler so I assume this is the problem. I cannot find a stock heat shield anywhere thats not rusted out (I live in Michigan) but I am sure I can find a universal heat shield to put on. I am wondering if the bedrug is going to melt as well not sure if anyone has any insight but I know it doesnt have any heat shielding in this area.

In researching soultions on the forum I see Noico is highly recommended but I am concerned about this melting or having issues as well. Would this stand up to the heat or should I do some sort of heat shield, Noico, and then bed rug?

This is an off road jeep mainly and the floor pans do have some rust issues, I have replaced the bad spots but I assume Noico should not be applied on rust. I was already planning applying POR-15 prior to the bedrug but I dont know how that will stand up to that much heat either.

Any suggestions are helpful.
 
Noico won't melt and will definitely do a great job of keeping all he heat out!
 
Yeah, mufflers don't get hotter than the normal exhaust pipe. It's got to be the cat, and if that's in it's stock location, the real issue is not one of insulation (although a heat shield might be missing but it doesn't sound like that's the issue). Need to figure out why the cat(s) are getting so hot.
 
Its a 1997 TJ so it only has 1 Cat and the entire exhaust is less than a year old. The rear passenger floor is right above the muffler. Below is what I replaced the stock exhaust with which was rusted through when I purchased the Jeep. There was no heat shielding before so I assumed it didnt need it but now I think it must have been removed. Jeep runs very well, plenty of acceleration so I dont think the cat is clogged.

Magnaflow Cat
Dynomax Muffler/exhaust
 
You can see the Cat is under the front passenger floor pan, which has no heat issues.
7562C8ED-ED8B-4E45-B171-9FC8D4230468.jpeg


Here is the muffler, the two holes above the rear of the muffler are the rear floor pan and the mat melted right between those two holes.
E3D14295-6F1C-4560-888D-97B2CAA83504.jpeg


8ACE529D-6645-4E4D-A283-E62C280E4A15.jpeg
 
Do you think I could just do this rear section or would I need to do the whole floor? Does it effect the bedrug in any way?

I'd do the entire floor, that's what I did. However, you could do just the rear.

It doesn't effect the BedRug at all. Mine had Noico and BedRug over the top of it.
 
Pretty sure mine has a heat shield around there. I'll look when I get back in town if somebody else doesn't beat me to it. Nothing should get hot enough to melt things except the cat. Something isn't right. Other things can make the cat get real hot besides it being clogged. Retarded timing or over fueling can do it.
 
Pretty sure mine has a heat shield around there. I'll look when I get back in town if somebody else doesn't beat me to it. Nothing should get hot enough to melt things except the cat. Something isn't right. Other things can make the cat get real hot besides it being clogged. Retarded timing or over fueling can do it.

I have found a few instances of this same occurrence in researching this but since the exhaust changed on the later models I dont think this is common. This is also a higher flow muffler so I agree that something else might be going on, I dont have any MPG issues which would reflect over fueling and if timing was off I would have performance issues which I dont. I think this melted while spending a 90 degree day in the sand dunes at crawling speed. Never overheated or anything and I am not having any other issues I would hate to go looking for a problem.
 
I've had the similar issues but with both front floor boards. I read somewhere that the interior shift boot is the issue. mine is shot on my LJ, I have added that heat barrier on the bottom with poor results. Going to try the shift boot next.
 
I have found a few instances of this same occurrence in researching this but since the exhaust changed on the later models I dont think this is common. This is also a higher flow muffler so I agree that something else might be going on, I dont have any MPG issues which would reflect over fueling and if timing was off I would have performance issues which I dont. I think this melted while spending a 90 degree day in the sand dunes at crawling speed. Never overheated or anything and I am not having any other issues I would hate to go looking for a problem.

I just did a cat back on my 06 on Saturday and there is a heat shield above my muffler. I think you are on the right path with some type of shield. 90 degree day crawling in the sand dunes probably did it IMO.

Time for the 1 inch body lift to help with cooling distance. Now you have a reason.....
 
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