I have a 2000 eclipse GT that I just replaced the stat & radiator in & so my problem begins. Engine heated up fine & the gauge was where it was supposed to be.After 10 min. the gauge fell to cold as if the engine wasn't even running. I have heat coming out & no matter how long the engine runs gauge is not moving. I was in the process of getting the air out when this happened. I've only got about half the fluid into the radiator that is required but I can't add any more because it's just coming out the top of the radiator. I don't want to keep running my car because everything is running to hot because the fan is not kicking on due to the temp gauge - I assume because fan was working fine initially.

 

hook the wire to the temp sending unit