Hi all! Our 2010 258 is overheating only when the driver has the idle raised with the control knob. It happens pretty quickly, he claims that starts within minutes. He uses the Idle up while operating the PTO. When the truck regenerates, it raises the Idle up to about the same rpm and the truck overheats then too. We've Replaced the Fan clutch, Blew out, Drained and Refilled the radiator. Other than those exact instances it will always run cool at idle and driving down the road. Thanks for any input!