exhaust smell in cab '21 denali

[steiny93]

Anyone getting an exhaust smell in the cab?

Wife's '21 denali, first time in the cold weather (-20F) we had an exhaust smell in the cab. Dealer worked on it, said something about a bad check value, (and it got warmer outside) smell went away. Now this winter (-20F) it's doing it again.

It only has the smell when the vehicle is barely moving or stopped with a breeze from the rear.

It isn't the regen smell, it's a very smelly diesel exhaust smell. Imagine a JD 4430 starting at 0 degrees in a pole barn, that's the smell and you'll get it for a whiff then its gone for a minute or two then happens again.

Anyone else?
It goes in again this week for yet another warranty visit, confidence waning.

 

[Holy Roller]

That’s exhaust odour before emissions treatment. Either at first start up - or your leak is somewhere near the engine itself.

 

[steiny93]

That’s exhaust odour before emissions treatment. Either at first start up - or your leak is somewhere near the engine itself.

That is an excellent point; the leak has to be hyper early in the exhaust system.

This smell isn't at startup, I've only noticed it after the vehicle is up to temp and being used (drive throughs, stop signs, off road low speed, etc).

 

[StephenPT]

Any MIL/DTC codes? This might apply to you or it might apply even if the MIL hasn't tripped.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10209120-0001.pdf

Also, this one is of interest, but it sounds like you've already had this fixed. https://gm-techlink.com/?p=14365

One more - https://gm-techlink.com/?p=16839

 

[steiny93]

nothing lit on the dash, I haven't plugged in a scanner to see if their are any pending codes

The techlink of 14365 is what 'I think' they did last winter, I got the intel from my wife who got it from the service writer (3 layers of misdirection )

 

[Larsonxjs]

Anyone getting an exhaust smell in the cab?

Wife's '21 denali, first time in the cold weather (-20F) we had an exhaust smell in the cab. Dealer worked on it, said something about a bad check value, (and it got warmer outside) smell went away. Now this winter (-20F) it's doing it again.

It only has the smell when the vehicle is barely moving or stopped with a breeze from the rear.

It isn't the regen smell, it's a very smelly diesel exhaust smell. Imagine a JD 4430 starting at 0 degrees in a pole barn, that's the smell and you'll get it for a whiff then its gone for a minute or two then happens again.

Anyone else?
It goes in again this week for yet another warranty visit, confidence waning.

I’ve gotten a little smell as well using the remote start to warm the cab.

By the way this is poetry - “Imagine a JD 4430 starting at 0 degrees in a pole barn,” few people will ever experience that.

 

[steiny93]

UPDATE on the original issue

Dealer just called, turbo is bad, they have requested a new one which happens to be a 'direct ship' only component. No ETA as to when it will arrive, dealer said to expect weeks, likely not months.

They don't offer Denali's or any full sized suv's as loaners while this is being figured out. Not impressed to say the least.

 

[dbphillips]

That’s worrisome. Ours is doing something similar, but also a lot of smoke at startup.

 

[steiny93]

That’s worrisome. Ours is doing something similar, but also a lot of smoke at startup.

If you are getting exhaust smell in the cabin, take it in, their are a few notices out (notice the 3 listed towards the top). The dealers can test for leaks pretty easily.

On this Denali, the amount of smell in the cabin seems to depend upon the temp of the vehicle at startup and if you have the hvac in recirculate mode or not. Recirculate mode helps alot. If the vehicle is cold (< 10F) the exhaust smell is much stronger then if the vehicle is say 50F. So, this one always sitting in a heated garage, the frequency of stink was low; but leaving it outside over night; it'd be near undrivable until it was up to operating temp.

 

[steiny93]

UPDATE AFTER LATEST FIX
Dealer received the parts and put them on the truck (Wednesday), they drove it and tested it a fair amount ~20 miles.
We picked up the truck, exhaust smell gone.

Drove it about 10 miles.

Still getting exhaust in cabin during cold startup.
And...
Check engine light, service emission system msg, reduced power msg on the dash.

Truck is back at dealer, they are assuming a failed weld on the valve but will test to verify.