DEF Regen causing camper trim to melt?

Sledguyry · June 29, 2021

I pulled into my campsite last weekend and immediately noticed that the plastic trim on the exhaust side of my new 65k fifth wheel looked like this. I’m not sure what to do next. Could this possibly have been caused from DEF Regen? I didn’t get any messages that a Regen was happening. I’m 99% sure I didn’t hit anything. Anyone have any thoughts on this?

Sledguyry · June 29, 2021

Here’s another picture.

Edited June 29, 2021 by Sledguyry

Thankful · June 30, 2021

It certainly looks like a heat source melted it. I'd talk to the dealer and ask him, although I doubt he will be willing to admit it was caused by a regen.

unit · June 30, 2021

Fortunately, It looks like an easy repair and the rig didn't catch fire. I think you'll need a heat shield on that portion of the trailer to keep from having problems in the future. My Airstream has stainless rock guards on the front of the trailer that most likely do the trick for me. It shouldn't be too hard to rig a couple of standoffs and attach a piece of stainless steel to them to fix the problem.

The heat shield wouldn't need to be as big as shown in the photo below but it gives a good idea of what's needed.

Edited June 30, 2021 by unit
Added text.

rmsmis · June 30, 2021

Sorry you had this happen, but I'd say with 99% certainty this was due to a regen. Usually you won't get a notice that a regen is taking place other than lower MPGs, but keep in mind that your exhaust temp can get up to 1,300 degrees during a regen cycle. I'd suggest any of three options; buy a 5" 45 degree angle tip and bolt it on to the outlet when you tow, cut the outlet a little shorter and permanently mount a 45 tip on the end, or buy a DPF-back exhaust that comes out the side. If it happened once, it will happen again unless you point the exhaust away from the trailer. I pull a travel trailer and have some extra room so the stock angle is fine, but your fifth wheel is closer to that high heat.

Sledguyry · July 1, 2021

Thanks for the replies everyone. I am glad you all agree and I’m not losing my mind. Lol. Looks like I may need to invest in Rock Tamers with a heat shield on the passenger side flap. I think that should prevent this in the future.

redwngr · July 1, 2021

They don't give a message to indicate when a regen is occurring.

(the keep driving message you may have read/heard about is if regens have been unsuccessful after multiple attempts and the soot level is considerably higher than the level that would trigger a regular regen.)

Another JR · July 2, 2021

My cousin once had the exhaust from his little Mini Cooper (gas) melt the tire of his bicycle on a rear rack on a highway trip. He couldn’t figure out what had caused it, then I noticed that little tiny exhaust pipe pointed at it from under the bumper.

Edited July 2, 2021 by Another JR

JW2020 · July 9, 2021

I had this exact thing happen to mine as well. The dealer was good about trying to figure it out and GM Engineering came out and checked everything but stated it was operating as designed. Apparently it is designed to melt your trailer. I asked about getting a 45 degree tip installed to push it away from the trailer but they couldn't give me an answer as to which point it could potentially void the warranty if something happened to the exhaust system. There's so much emissions crap in there now I don't want to piss off the system and start throwing any codes. However, you should complain to them. The truck is DESIGNED to pull fifth wheels and goosenecks. If the truck as designed is melting the trailer, then something is wrong with the design. They should compensate you for the damage so you can get it repaired. Then, yes, as others have suggested, just put a heat shield on the trailer. Works well. Also, I put over 1500 miles on my trailer before this happened. Basically flat roads to slight inclines do not seem to cause this issue. I believe it is because the speed of the vehicle on the freeway keeps it a bit cooler. For me this happened in the mountains of Colorado where airflow isn't very strong on massive uphill grades and regens are more likely due to the strain of the grade on the engine. Just my two cents, but honestly, this is stupid on GM's part. Just have the pipe exit the vehicle at 90 degrees like they used to...

nards444 · July 9, 2021

14 hours ago, JW2020 said:

I had this exact thing happen to mine as well. The dealer was good about trying to figure it out and GM Engineering came out and checked everything but stated it was operating as designed. Apparently it is designed to melt your trailer. I asked about getting a 45 degree tip installed to push it away from the trailer but they couldn't give me an answer as to which point it could potentially void the warranty if something happened to the exhaust system. There's so much emissions crap in there now I don't want to piss off the system and start throwing any codes. However, you should complain to them. The truck is DESIGNED to pull fifth wheels and goosenecks. If the truck as designed is melting the trailer, then something is wrong with the design. They should compensate you for the damage so you can get it repaired. Then, yes, as others have suggested, just put a heat shield on the trailer. Works well. Also, I put over 1500 miles on my trailer before this happened. Basically flat roads to slight inclines do not seem to cause this issue. I believe it is because the speed of the vehicle on the freeway keeps it a bit cooler. For me this happened in the mountains of Colorado where airflow isn't very strong on massive uphill grades and regens are more likely due to the strain of the grade on the engine. Just my two cents, but honestly, this is stupid on GM's part. Just have the pipe exit the vehicle at 90 degrees like they used to...

Yeah I dont get the location of the exhaust back there like it. These trucks are built and bought to haul and they should know better. Beyond melting trailers, what about people standing behind it, I get it that it doesnt regen at idle. Yeah dumb design.