SilentCool

2003 Mitsubishi Lancer ES
2.0L 4 Cylinder

I have been having an issue with my car where the cooling fan is always running. As long as the car has power (key turned to "ON" position) the fans will come on. I went ahead and replaced the Cooling Fan Controller Module since it is usually the culprit. After replacing the module, the issue was resolved. Fans will not come on until AC or temperature is above threshold. At this point I assumed everything was in proper working order. After a few days however I noticed that my temp gauge started going above normal operating temperature so I replaced the cooling fan assembly since I discovered that only one fan was fully functional. Well....now both fans run perfectly. Unfortunately this didn't fix my issue. Temperature gauge needle would reach about 3/4 on the guage and then return to normal operating (a little less than half on temp gauge) temperature, it would repeat this a couple times during normal vehicle operation. It is a bit more prevalent in stop and go traffic.

I suspect it can only be one of two things at this point.
1. Thermostat
2. Temperature Sender/sensor

Should I replace one or both? I'm assuming that the thermostat should be an OEM replacement, correct?
Any help would be greatly appreciated, thanks.

gt_phdm

My guess is the sensor. Thats just me tho. I'd say replace the sensor first then observe. Anything engine related, OEM is the answer.

SilentCool

Thanks man, I suspected t he sender and not necessarily the sensor but replaced them both, along with my thermostat. Everything is all good for now.

SilentCool

^^^^^^^good advice. Have you been able to solve this issue?