[folivier]

Looking at Richards #'s for his series 60 and talking with others I feel my engine and cooling system has a problem. I'm towing 6500 #. Climbing some of the hills going to the rally my engine temp got up to 216 once, other times it got to 208, 210. Once we left and headed north on 65 I kept the speed down to 58 and the temps were a little cooler. But as we drove on I-70 to Salina and the ambient temp got to 100 the engine was running anywhere from 198 to 212 on the hills. I did have to change the fuel filter Monday afternoon since it was plugged. Tuesday we continued to Colorado and the ambient temps were 70-80 and the engine temps ran cooler, from 193 to 208 on the harder hills.
I'll occasionally see the engine temp go from 198 to 205 even on flat ground.
So where do I start? Should I have the thermostats changed first?
Get the radiator flushed and refilled?