06 PSD 6.0 4x4 about 70,000 miles air intake and exhaust. We were recently pulling our toy hauler when temp spike, return to normal in 20 sec, let it cool puked out about a gallon of coolant. Drove home 30 min into drive on flat ground got a check engine light with wrench light and limped her home. Took her to a dealership and they started diagnostic test said the found an over boost code, and the headgasket was damaged which pressurized the coolant tank after further investigation they said the turbo was the cause of the damage and they wouldnt honor extended warranty.they also said the center section of the turbo was frozen. I never lost boost. PLEASE HELP this doesnt make any sense.

 

If the vanes on the turbo are stuck it can definitely cause an overboost.

 

what does the over boost feel like

 

I don't know that you can "feel" it, but if your boost shouldn't go any higher than 27 - 28 psi at wide open throttle on a stock truck.

 

The diagnosis seems plausible. But I'm not clear on why they are denying warranty coverage. Your turbo should be covered. However, the aftermarket intake might be what they are laying this on. Unfortunately, if they want to be *********, they probably got you on that. Even though I don't believe it caused this problem, and those turbos are known to gunk up and stick.

If I was paying the bill, I would pull it out of a Ford shop and get an independent second opinion.