2012 2250 EGR Tune up and other things

[tree98]

Just replace the doser. If all the sensors are original chances are the doser is too.
You need to get the Cummins insite 7.6.2 program and an inline adapter like this https://rover.ebay.com/rover/0/0/0?mpre=...2895748426
That will tell you if your dpf is plugged and a lot of other diagnostics to help you work on your engine. It's a MUST if your going to own one of these motors.
For your coolant loss problem you'll need one of these https://rover.ebay.com/rover/0/0/0?mpre=...2177380668
You might also need an adapter that this doesn't come with, you'll have to do the research. Once you get it, pressurize your cooling system and find the leaks.

Your also gonna need that inline adapter to let unilevers in :)