Suddenly stinky diesel

[Kmongene]

I'm new to the site so not sure if I'm posting my question in the correct category.
I have a 2007 Chevy 2500 HD 4WD. It has 125K miles
I'm the original owner.
There are no check lights on or DIC messages displayed.
The fuel economy has not changed. Still very good.
There is no black or other color smoke.
All gauges are in the normal range and the truck seems to be running great as usual.
Except for this; suddenly there is a very strong nearly unbearable diesel exhaust odor. Not to be mistaken with raw diesel fuel. It is for sure a burned diesel smell. When going down the highway you can't detect it, but at a stop the cabin is saturated with the odor. If you stand outside the vehicle you can smel it strong. If you open the hood with the engine on the odor is strong.
This vehicle has never ever had this problem. The oil was changed 2 days before I noticed the problem. I do all my own maintenance. I used Delo 15 w 40. There are no fluid leaks on this vehicle.
If anyone has any experience or advice I appreciate it. Jim in Nashville, TN

 

[DAVe3283]

If you've recently switched from Delo 400LE (CJ-4 spec) to Delo 400SDE (CK-4 spec), it could be increased oil consumption / blow-by. My motor does not like the new oil spec. I can smell the oil burning off at stop lights, and it is a diesel-y smell more than oil smell.

Or, that could be a coincidence (stock motors are very forgiving on oil), and you had an exhaust leak form. Check up-pipe, down pipe, EGR, and turbo gaskets for signs of a leak.

The fact that you smell it under the hood is what makes me think of an exhaust or PCV leak. You shouldn't smell it under the hood even if you have failing injectors.

Sent from my Cat S60 using Tapatalk

 

[Burn Down]

I would suspect an exhaust leak as Dave mentioned.