Ive been having this problem for awhile... I had my radiator replaced about 2 or 3 months ago seems it was cracked, was under warrenty. But the problem is the truck got to 240 or so degrees before i noticed the idiot gauge even moved. Confermed by my scan gauge... And now after having it replaced my truck runs about 207-213 on the highway at 70 mph on cruse. If i put it back in 3rd and bring the rpms up it will go back down to 200ish. It always ran 198-202 before i had a problem. Im not sure if there is a air bubble in the line or the water pump is cashed. Or how to get the dealer to fix this, I dont want them to look at the stock gauge and say well its not moving its fine, cause it doesnt move til its over 220 anyways. What im wondering is if i take it back in do they have a better way to check the water temp other than the stupid C and H temp gauge? If not and they keep saying its fine and the motor pops a head gasket from geting so dang hot how can i cover my own ***.