Fan pulley, removal nessesary?

every minute you run that motor at 150 your wearing the walls like 200% faster than at 180. Get a hot stat. You could just run a spacer in front of the pulley, but restricting the flow of air through the radiator is probably easier. Cardboard works, just cut a hole in the middle for something to get through. If the stat is working, the coolant is restricted in the radiator anyway. I bet your stat is shot or absent.