Burning smell from brand new Diesel Sierra 1500

grrr027 · July 7, 2020

Hi everyone - new to the boards and first time GM owner. Just picked up a 2020 Diesel Sierra 1500 a week ago. I have put about 550 miles on it and noticed today a burning smell when parking it in the garage. Smells kinda like burnt rubber. This is also the first diesel I have ever owned. Any idea what this might be and if it is normal? I called the dealer and they said it may be the smell of the undercoating cosmoline that is generating that smell and should go away after 1000-2000 miles. Anyone else experienced this?

Thanks!

Sierra 3.0 · July 7, 2020

There is nothing to worry about. The truck likely hit its first diesel particulate re-gen and the exhaust components get really hot causing the smell. I have had the 3.0 liter and now have around 7000 miles. Mine did the very same thing and smelled awful. My old truck, a 2007 Chevy Duramax, also had a DPF and its first few regens smelled the same. It may smell like this for the first few regens but it will eventually get better and you wont notice it anymore.

Congrats on the new truck! I'm very happy with mine!.

grrr027 · July 7, 2020

3 minutes ago, Sierra 3.0 said:

There is nothing to worry about. The truck likely hit its first diesel particulate re-gen and the exhaust components get really hot causing the smell. I have had the 3.0 liter and now have around 7000 miles. Mine did the very same thing and smelled awful. My old truck, a 2007 Chevy Duramax, also had a DPF and its first few regens smelled the same. It may smell like this for the first few regens but it will eventually get better and you wont notice it anymore.

Congrats on the new truck! I'm very happy with mine!.

Awesome, thanks! I had read a bit about that as well, and was surprised the service dept at the dealer didn't mention it. It was a bit alarming spending that much cash on a new truck and noticing the smell, haha. Being that I don't know what I don't know about diesels, I figured the forums here would be a great place to start. Appreciate the reply! So far, I love the truck... by far the nicest i have ever owned and it drives like a dream.

newdude · July 7, 2020

43 minutes ago, grrr027 said:

Hi everyone - new to the boards and first time GM owner. Just picked up a 2020 Diesel Sierra 1500 a week ago. I have put about 550 miles on it and noticed today a burning smell when parking it in the garage. Smells kinda like burnt rubber. This is also the first diesel I have ever owned. Any idea what this might be and if it is normal? I called the dealer and they said it may be the smell of the undercoating cosmoline that is generating that smell and should go away after 1000-2000 miles. Anyone else experienced this?

Thanks!

It might be a combo of undercoat and DPF/exhaust smell. Burnt rubber would be from the undercoating, and might be worse if they got some on the exhaust. The DPF odor will diminish after the first couple of regens.

Edited July 7, 2020 by newdude

grrr027 · July 7, 2020

48 minutes ago, newdude said:

It might be a combo of undercoat and DPF/exhaust smell. Burnt rubber would be from the undercoating, and might be worse if they got some on the exhaust. The DPF odor will diminish after the first couple of regens.

Thanks, all very helpful. Curious on the regen cycle - do Sierras automatically run them when needed and if so, should I expect to see a dash indicator when it happens?

BurnsMax · July 7, 2020

53 minutes ago, grrr027 said:

Thanks, all very helpful. Curious on the regen cycle - do Sierras automatically run them when needed and if so, should I expect to see a dash indicator when it happens?

Yes they run as needed and on there own. The only time you will get an indicator is if you have had several incomplete DPF regens. Then you will get a message on the dash stating you need to keep driving. I can tell when mine is in a regen especially in the city with stop and go. It will have a more of diesel sound. The other way to tell is to use a wireless or bluetooth OBII scanner and app with the DPF regen loaded on one of the dashboards. It will have a 1 when in regen and 0 when not in one. Regens occur 100-200 miles with city driving and usually 400-600 on mainly highway miles. The regens will get less smelly after 3 or 4 of them.

bobbobtar · July 8, 2020

Mine started a re-gen today couple miles before I pulled up to the drive up window at the CU, when idling the exhaust is louder and the RPM's increase a couple hundred

grrr027 · July 8, 2020

All of this makes sense and sounds exactly like what I had going on. I noticed when in the drive thru today that it sounded much more like a diesel. Not gonna lie I kinda liked that part of it. Noticed a higher idle too. Drove more tonight and didn’t notice the smell at all. Appreciate all the input!

ILSilverado · July 8, 2020

Totally normal It should fade by the time you hit 5000 miles. The regen cycle will always produce a little smell even after 5000 miles.

when you are down 3 bars on the def gauge you can add a whole 2.5 gallon jug of def.

Otif · November 30, 2020

Hi everyone, I’m experiencing the same thing. Just took delivery of a 2021 Sierra with the Duramax on Friday, and noticed the smell last night when I parked at home. Naturallly, as this is my first diesel, I freaked out. The only difference with me is that I saw some smoke that looked like it was coming out around the passenger side headlight area. It went away after a few seconds, but freaked me out none the less. Is the smoke a part of the regen process as well? Thanks in advance

nik1176 · December 3, 2020

Hi Everyone....Like Otif I just got my '21 Sierra with the LM2 last Friday. Today I was getting really bad smells in the cab whenever stopped. It really would be helpful to have some sort of indicator when the regen is running.

Ironically, I happened to be on my way to the dealership to pick something up, and I asked the advisor about it. They said it must be an exhaust leak and they would have a tech look at it on Monday. Now I see this is 1) normal although a little ridiculous how bad it gets in the cab, and 2) the dealer should have been able to advise me of the regen cycle.

Thanks for the info!

AudiOn19s · February 8, 2021

Bringing this back up for a follow up question. Will the truck go into ad-hoc regen on very long downhill runs like through the mountains?

I smelled a little bit of smell on the first regen that smells somewhat alarming...almost like electrical components overheating much less than exhuast or brakes or something like that. I dismissed it as regen.

BUT....on a recent 2500 mile round trip I could tell when the truck was in regen on flat ground and never smelled anything in the cabin like i did on the first regen, however when the truck would go downhill for extended periods of time the smell (again best described as electrical fire) was VERY pronounced. and would go away immediately following the decent, almost as if it wasn't really in regen at all.

thoughts?

**edit** downhill runs were not in tow mode so it wasn't jake brake, and my application of brakes was sparing at best, they were not hot esp with air temps in the 20's and 30's.

Edited February 8, 2021 by AudiOn19s

BurnsMax · February 9, 2021

4 hours ago, AudiOn19s said:

Bringing this back up for a follow up question. Will the truck go into ad-hoc regen on very long downhill runs like through the mountains?

I smelled a little bit of smell on the first regen that smells somewhat alarming...almost like electrical components overheating much less than exhuast or brakes or something like that. I dismissed it as regen.

BUT....on a recent 2500 mile round trip I could tell when the truck was in regen on flat ground and never smelled anything in the cabin like i did on the first regen, however when the truck would go downhill for extended periods of time the smell (again best described as electrical fire) was VERY pronounced. and would go away immediately following the decent, almost as if it wasn't really in regen at all.

thoughts?

**edit** downhill runs were not in tow mode so it wasn't jake brake, and my application of brakes was sparing at best, they were not hot esp with air temps in the 20's and 30's.

You live in a cold weather state? I live in Minnesota and with this very cold weather I notice a burning smell from the DEF

AudiOn19s · February 9, 2021

Yes, ohio

TxAlarm · February 10, 2021

Glad I found this thread tonight. Just had the same thing happen on the way home from work and was kind of freaking out thinking something was on fire under the hood or even in the dash. Smelled really bad in the cab so rolled the windows down but that didn’t even help it was so strong. Oil pressure was very low and the exhaust sounded different, almost like maybe an exhaust leak. Guess I’ll give another 1k miles before I get too concerned. Dealer should definitely tell people about this. I almost pulled over on the side of the highway so that I didn’t do some kind of engine damage.