Start with EGR cooler. After parking the unit and letting it sit a bit, yank EGR solenoid. If it is wet or wet inside the intake, the cooler is bad. Either delete it (Do a search you'll get the info you need), or get one from BulletProofDiesel.com. Make sure you replace oil cooler as well. I did them both myself. It was not that difficult at all.
If you are blowing coolant out the degas bottle (I am sure you are) replace that cap as well.
Start with that information and go from there. Do some searches on the forum and you'll get it figured out.