Diesel exhaust in cab

[roundoz]

I have a 2009 quadcab 6.7. Stock setup. 135000 miles. About 5 or 6 times in the last 20k miles or so I have had fairly short periods of very bad exhaust fumes in the cab...enough to make my eyes water and give me a headache. I believe it is coming in through the fresh air intake. It can be if the truck is left idling in sub zero temps (it's a work truck and it keeps my tools and test equipment warm and is a sanctuary to warm up in periodically) or it can happen when I am driving at 60 mph. The only relief is by turning off the fan and opening the windows. It might last just a few minutes or for a half hour while driving. The dealer has been over it twice and found no signs of exhaust leaks or holes in the firewall or fresh air system.
This morning after travelling about 80 miles I stopped under a street light at an intersection and noticed smoke coming up apparently from under the passengers side front fender. Smelled that rich diesel exhaust smell again. Immediately thought I had diesel spraying on the engine (seen that scenario before ) so I pulled into a parking lot to investigate. No signs of anything out of the ordinary under the hood and the smell had pretty much gone.
So, ideas anyone? A very intermittent diesel leak that leaves no sign of itself behind?

 

[roundoz]

Or the other option....truck is in Regen (I'm sure with my mostly highway miles it doesn't Regen very often) and I have a bad exhaust leak somewhere that the dealer hadn't noticed....maybe egr, UP pipe???

 

[Cummins Powered]

Time to remove egr/cooler, along with a full turbo-back system.To me it sounds like a leak in the egr/cooler system, once you delete all the emissions bs, you'll experience no diesel smell in the cab, and no more leaking egr issues. There are several companies that offer egr block off plates, and off- road tuning. Black Market Performance AutoCal with EFI live tuning, and RaceME, offering code free, with longer engine longevity.

 

[roundoz]

I wish that was an option. This is my company truck. Not getting much help from Dodge or my fleet dept.

 

[roundoz]

Ok. I think I have it figured out, with your help and advice I read somewhere else to stick your hands around every part of the egr cooler and manifold and see when they come out black. It appeared to be at the very back of the egr cooler where it attaches to the exhaust manifold

 

[roundoz]

...I used a piece of tygon tubing as a stethescope (figured this out a few years ago ) and sure enough it is leaking out of there badly at idle. Didn't want to complicate the enquiry but in the last couple of thousand miles the truck has been making a high pitched whine from that general area either when slowing with the Jake or when accelerating hard...so I think I have found a twofer. Thanks for all your help. Will let you know if a new gasket doesnt fix the issues.