2014 Fiesta Overheating at Idle

[LunaRose]

Hi!

So my 14 Fiesta (1.6 4cyl) with about 73k miles has started overheating at idle probably about 5k miles ago. Noticed it first when waiting for someone (idling about 20-30 mins), and since then it's happened if I idle for more like 10-15 mins. 

I can't tell if the fan is kicking on or not, and I'm not sure if it's an issue with the thermostat. I've seen three issues on other forums: thermostat, fan, or the fan fuse may be blown. I'm just not sure. 

Would it be worth taking it straight to a dealership, or is it something I could possibly diagnose and fix pretty easily myself?

 

EDIT: I just realized this is a UK board. Mine is an American Fiesta, if that makes any difference.

[btmaldon]

Before you spend a load, try changing the expansion tank cap. If its not holding the pressure it will overheat and the electric fan is unlikely to kick in due to there being hot and cold spots in the engine. The coolant will not circulate properly. Failing that, check the expansion tank for cracks or leaks and then move onto the thermostat. The plastic housing has a tendancy to warp after so many years. Good luck.

 

[isetta]

It must be easy to tell if the fan is kicking in, when the temperature is right up very high open the bonnet (hood in USA) and see if the fan on the radiator is running (don't stick your hands in it). This assumes it is not losing coolant. 

Is it losing any coolant?