Mondial T Thermoswitch

It appears as though mine has gone bad...still have a bit of diagnosis to do to confirm. I have searched the archives and seen a number of folks swapping out for other that kick in at a lower temp...can anyone elighten me as to what the rating is on the Mondial T and then how to figure a suitable replacement if I do not go OEM?

Also, I have never replaced before nor have I done a coolant flush. I assume the location of the switch indicates it is going to drain all over me. First, do I need to flush and refill? Second, the combination of coolant tanks, radiator and lines leads me to belive this could be quite the effort...best to let someone else do it or is this about as difficult as changing the oil?

Thanks,
JMG