The heating gauge goes 3/4 way up after about 30 min driving at highway speeds. It goes down fairly quick if you turn on the heater. I took it in to a mechanic and they changed out the radiator fan. The car continued to overheat and they said I should change out the ECT sensor which I did along with the fan switch and thermostat and it continues to overheat. The last time I got the car hot, I turned off the heater and noticed that the radiator fan was not on even though the gauge was over half way up. If it is the fan, my question is why does it over heat when I have the A/C is on which activates the fan? What is my next step in fixing this problem?

 

so both of the fans are working? and still over heating?

 

Fans are working when A/C or heater is on. Last diagnosis from the mechanic was fan was not kicking on until too late but was hoping changing the ECT sensor and Fan switch would fix that.

 

is your radiator in good condition? did you bleed the radiator? after installing new thermostat?

 

I followed the instructions I had. I ran the car with heat on and radiator cap loose. I then topped off the radiator again once it had ran through. I put as much fluid back in as I drained out. I recycled since the Mechanic just changed it out this week when installing the fan. Could it be a plugged radiator?

 

kinda hard to say...is the radiator fluid flowing? hows your radiator cap? hows the springs? any leaks?

 

Could be a couple problems happening at once I suppose, Fan not kicking on unless A/C is on coupled with a plug in the radiator?. Took it in to the Mechanic today since i don't have the time to diagnose. Will post what I figure out.