The water pumps on the Sable as well as the Taurus have weak impellers. They tend to become a sacrificial anode - wear away.
Most Garages will not check the water pump if it is not leaking. Once the impeller has been eaten up it can no longer circulate water and the engine will over heat.
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theyre maybe an air bubble in the block causing it to overheat,or it could also be a bad water pump
you might want to check for a blown head gasket or a cracked head or block. espically if it loosing water out of the radiator with out leaking on the ground.
Have you heater core replaced.
needs a new heater core
This is normal. Only one fan is suppose to work with the A/C on. The other fan works when needed.
you replace that with coolant in the summer or hot areas
no
sounds like you have a cracked head
fan clutch?
check your fan clutch if its weak it will overheat
Park over a large piece of paper or cardboard overnight, make sure it will not fly away. if the antifreeze is towards the front of your car, thre is a possibility that your radiator, or one of your hoses has a hole. if the leak is more towards the center of the car, behind the passenger tire, your heater core has a leak and must be replaced.
Sounds like the signal switch is at fault.