2007 5.7 Megacab Exhaust Temperature?

[MonkeyTrev]

So I bought an 07 Megacab 1500 with the 5.7 back in august of 2024. I love the truck it’s exactly what I was looking for minus being a gas instead of diesel. It was just too good of a deal to pass up.

I noticed early on that the aftermarket exhaust the previous owner installed was very very rusty so I climbed underneath to cut it off and realized all the hangers after the muffler had rusted away and the exhaust pipe had actually melted through the spare tire under the truck! So I chopped off the exhaust right after the muffler and installed downpipes. I just noticed today that the emergency brake cable that is installed on top of the rear axle has a black plastic coating. The black plastic coating is melted and peeling away right where my newly installed down pipes come out.


Is it normal for the exhaust almost to the tips to be able to burn through a spare tire and not right after the muffler be hot enough to melt some plastic cable coating? It’s roughly 2-3” from the emergency brake cable.

I have included pictures of the melted tire before I chopped the pipes off and after I installed the downpipes. You can actually see the black coating on the brake cable in the picture before it was melted off.

If not normal - What could be some causes?

 

[rzr6-4]

Exhaust is hot, can confirm. Rubber gets very soft and eventually burns at 300-500F. Exhaust will probly be leaving the tailpipe anywhere from 300-1000F.

Melting your parking brake cable is kinda on you, your tips are pointed directly at the top of the axle where the cable is.

 

[MonkeyTrev]

Exhaust is hot, can confirm. Rubber gets very soft and eventually burns at 300-500F. Exhaust will probly be leaving the tailpipe anywhere from 300-1000F.

Melting your parking brake cable is kinda on you, your tips are pointed directly at the top of the axle where the cable is.

Yeah, I know the parking brake is on me. I just wanted to make sure I don’t have an engine issue that is causing extreme exhaust temps.

 

[caulk04]

Is there evidence of the truck having done burnouts? If someone was to do a burnout contest and beat it like a rented mule, exhaust often becomes nearly transparent from heat.

 

[crash68]

@MonkeyTrev if the previous owner towed a trailer for lots of miles, it's not inconceivable for the exhaust temps to be hovering close to the 1000° degrees. Add a free flowing aftermarket exhaust and it's entirely possible to have +800° radiating from the tailpipe. There's usually a heat shield in between the exhaust and the spare with air gaps.
A 1500 MegaCab is basically a 2500 with a lightened up suspension, popular for towing trailers with.

 

[MonkeyTrev]

@MonkeyTrev if the previous owner towed a trailer for lots of miles, it's not inconceivable for the exhaust temps to be hovering close to the 1000° degrees. Add a free flowing aftermarket exhaust and it's entirely possible to have +800° radiating from the tailpipe. There's usually a heat shield in between the exhaust and the spare with air gaps.
A 1500 MegaCab is basically a 2500 with a lightened up suspension, popular for towing trailers with.

The previous owner towed a 5th wheel camper around Tennessee. So I’m sure that is the results. Lots of hills and lots of RPM for the 5.7.

 

[jws123]

Tail pipes are very cheap and easy to install I honestly would put it out the back like its suppose to be.

 

[MonkeyTrev]

Tail pipes are very cheap and easy to install I honestly would put it out the back like its suppose to be.

I plan on installing a cat back system. The downpipes were just a temporary.

 

[crash68]

I plan on installing a cat back system. The downpipes were just a temporary.

Be sure to inquire with @Nick@GotExhaust he's a forum vendor and very knowledgeable on what exhaust systems work on these trucks and give you the sound your looking for.

GotExhaust.com

www.ramforum.com

 

[Nick@GotExhaust]

The parking brake cable (as mentioned) is due to the tips being aimed at it.

As for the spare being melted, with the amount it was rusted it could have even been leaking at that section and heat escaping that spot even more. With the fact that they were towing a 5th wheel its totally possible.

As far as a new catback system shoot me a message if you would like a quote on anything. We got the MBRP system in stock for the megacab 1500 right now.