A head replacement is pretty advanced.... Not so much the actual head, but all of the little stuff that goes along with it. That is where they usually screw up.
My dealer constantly tells me that their diesel mechanic is one of the best in the country.... Yet I most always have to cleanup after him. Stupid stuff that should not happen. He basically doesn't pay attention or care enough to do things right. Probably just in a hurry to beat book and that means shortcuts.
The latest?
He had to remove my DEF tank for a repair. WHen I next filled it, the I found that the vent hose fitting was ripped off of the side of the fill tube. The dealer (Sands Chevrolet of Glendale) Offered me the parts at their supposed cost. 220.00 and they would do the labor. I found the exact GM AC Delco part for 85.00 and did it myself. Doing your own work behind a so called mechanic is an eye opener. It was obvious that he did not totally remove the tank as he should have. He let it hang from the fill/vent hoses while he replaced the tank heater assembly. That is what broke the fitting.
No way I was giving them more money to fix what they broke.