[tucsonjwt]

I'm not sure why you need to remove the fan in order to remove the belt - you can thread the belt around the blades of the fan and slip it off - I must be missing something here.
There is a rule of thumb on belt deflection based on the length of the belt, but I just tighten until the belts don't squeal because I have an air pump, which means that the belt has to be very tight in order to not squeal.
The fan is attached to the water pump pulley with 4 short threaded studs and nuts (usually with lock washers). If you do remove the fan you might want to replace those studs and nuts/washers since they tend to seize up and not want to turn after years of being in place.