His ran low on coolant. He speculated it was due to a leaking EGR. The larger factor was human error in thinking there's still coolant in the system when it's visible in the degas bottle.
FCA is in the process of replacing EGR's with a redesign. It's okay if you disagree with me that, with the proper tuning, the emissions components aren't that bad.
So says the guy that's actively looking for a pre-epa gde tune with the off-road option so he can install it when his emissions equipment fails.
It's not if the DPF, the def pump/scr or the EGR fail, it's when. Even with proper tuning those parts fail often and are expensive. Yes gde's new tune will most likely prolong the life of these components, but I guarantee they will still fail, soot is still circulated back through the engine, especially when cold, there is a lot of unburnt fuel because the truck needs to run rich so it won't die. There is no way around that and keep the engine running and that is a lot of soot going back into the intake in a cold engine caking things. Therefore the EGR will still cause reliability issues.
I'm 100% certain the EPA would love to eliminate diesels. As long as they get their way and enforce the emission standards they have, diesels will be unreliable.