I have a 2005 3500 Savana Van with a Knapheide body on the back. Truck has 170k miles. Problem is we cannot get it to run at 210. If it is over 80* outside it will run hot (Around 240-255) and won't cool off until you get on the interstate for a few miles. We have removed the rad and condenser and cleaned spotless. Also has new GM 4L80E trans, coolant was flushed and replaced. I need this truck for work and it spends alot of time in the city traffic so it running hot isn't an option. I hoped someone on here would have some suggestions.