I have a 2015 2500 with 29,000 miles on it now and today when I pulled up to a red light I noticed smoke coming from under the hood which I immediately pulled over and popped the hood and noticed smoke coming up from the left side of the motor. I thought I smelled the "OLD" diesel exhaust smell and drove directly to the Chevy dealer to have this looked at only to find it was not smoking any more. I got the diesel tech out there and we looked it over and he thought it may be the A/C condensate line draining onto the exhaust. I never turned the truck off and could only keep an eye on it to see if it happens again. Well I drove straight home (about 5 miles) and I noticed a small amount of smoke again coming from left side again but it just smelled like hot smoke and not diesel exhaust so I got my phone to record this but before I could start recording, the smoke stopped. Has anyone else had anything similar happen? It has never happened before so why now? 29,000 miles later it starts. I am concerned that this may be something more as the tech told me that if it were the diesel exhaust fluid then that stuff will eat the finish off of pretty much anything. Somebody help please.