[jcus]

The cooling water temp has a lower "limit" determined by the thermostat in the engine. My 93 coach has a direct drive fan and the engine runs at the setting of the 180 degree thermostat in the engine regardless of outdoor temperature unless headed up a steep hill on a hot day, then it rises a bit.

So, if your engine is running cooler than the coolant thermostat in the engine you probably have a failed thermostat.

I believe my thermostat is already open at 180 f., and the fan goes to high at 199 and drops the temp to 194, then goes to low again till temp goes up to 199 again. But as my water temp stayed about 195, am thinking the high manifold temp was forcing the fan into high mode.