2016 Fiesta SE 1.6L overheating

[JustAGuy]

I have a 2016 Ford Fiesta SE 1.6L (5 Speed). It has 57,xxx miles and it overheats when idling. It never overheats while driving, even with max A/C on. Only overheats when idling (with or without having A/C on) for 10-20 minutes.
I’m wondering if this is a common issue. I will be starting the diagnostic process tomorrow. My first step will be checking if the fan is turning on or not. My coolant isn’t leaking out, so that seems like a good start. I will chase the issue from there. I’ll post if I find the problem, in hopes of helping anyone else who runs into this problem.
Feel free to comment and help me, if you’ve had this similar problem before.
Thanks!
-JustAGuy

 

[Handy Andy]

You may have two relays but one has burned out it's contacts or some other internal failure - best to check your manual and locate these two relays. For one is for Engine Fan cooling while the other is for AC - fuses too - make sure the condition of the fuses is also not corroded or otherwise broken or compromised.

You'll hear the AC fan relay kick on so if that turns the fan - that relay is good, the other one might need replacement or further tests.

Look on Page 168 of the owners manual - two relays might be present - one R57, and R50 - of you only have one relay and it's position in the R57 spot, then the issue is around the wiring and sensor failure on the engine block by the outlet hose hear the back side of the motor by Cylinder 4 - and the spark coil ignition module that covers or blocks it.

Else you'll have R50 which looks more like a conventional Light or headlamp relay - that is your high-speed cooling fan that also may use a separate wire to run itself thru a module on the radiator shroud then onto the Fan. This module - which is a low-speed wirewound blower resistor - also has a special component that is a thermostatic switch diode that turns on to bypass the resistor when the heat in the radiator is hot enough to affect this component. Location? - it's near the top on that shroud in a recessed spot near the AC condensor dryer container. That part is in the spot it's in so it can feel the heat of the air temperature and turn on that switch to bypass the resistor (acts as a short) letting full current into the circuit to let the Fan run at full-on high speed as needed else it runs slower and uses less current so it doesn't load down the electrical system while it tries to keep the system cooler for a longer length of time.

This thread is for another type of vehicle but might shed light on your situation...
https://www.fordfiesta.org/threads/st150-radiator-fan-not-engaging.8907/post-24260
https://www.fordfiesta.org/threads/temp-sensor.8983/post-24610