my radiator fans want to come on to soon, about 20 degrees to soon. i have tried two different fan swiches, at different temp settings with the same result. i have also replaced all cooling componets accept the water pump. coming on to soon also means they never shut off, unless i kill the motor. stat is 180, switch is 200-185. can anyone figure this one out.

 

i replaced the water pump. checked the fan switch with an ohm meter. it seems to me i have a hot spot on this part of my block, is this possible?