I've had my truck to the dealer three times now for the same problems you are having. Each time they fix something then charge me the $100.00 deductible. first it was the egr cooler needed to be cleaned, still puked. Then it was, replace the egr cooler $100.00 still puked. Then it was the degas bottle, not under warrantee, $230.00 still puking. Finally I passed by a local diesel shop and brought it in and let them look at it. They have this nifty little vial type device with a conicle rubber stopper at the bottom. This fits snuggly into the degas bottle and is filled with liquid. you start your truck and if it boils over(mine did in about 10 seconds) then it's one of two things bad egr cooler or head studs. Next, they add a blue liquid and if it turns green then supposedly you have problems meaning bad head gaskets or worse warped heads. I've never heard anyone on here mention this type of test to check for head studs so maybe this will benefit you. Yes, mine also turned green. I have about 10k left before I hit the 100k mark, so I will be bringing it back in. Now, you would never know there was a problem as my truck works like I just drove it off the lot, but I'm constantly adding coolant.
Scott