I just put the water and oil gauges on my 01 500 HORSE today.
The book says that the fan should kick on at 180 degrees but Im seeing 193 on the gauge.
Its suppose to kick off at 149 degrees but Im reading 190'ish when it stops.

Not having coolant will prevent the fan from starting - no coolant, no hot water to heat the switch.

Make sure to fill the radiator - not just the coolant over flow bottle.

Trapped air in the system can cause a overheat problem Simular to no coolant (above) Run the machine with the cap off until the fan comes on and keep the radiator full. You might blow extra coolant out the overflow but that has not been a problem.

I do recommend a gauge. On the last ride my idiot light died and my only overheat warning was when the coolant started boiling out of the over flow bottle and the guy behind me smelled it before I became aware of it. Alone - I could have burned the engine up.

If you have a newer machine that shuts down when it gets hot - its nice to know how hot its getting before THAT happens. It took us until midnight to get out of one forest thanks to that feature.