Hi!

I own a 2010 KA zetec.

I bought the car in January this year and have had no problems until around a month ago. After a 15 minute drive to work one morning i parked up and “Excessive radiator fluid temperature, stop and switch off” message was displayed. I checked the water/coolant & oil level after work (gave the car all day to cool) and they were fine. The car drove home fine and hasn’t shown this message again until the last few days (a month later).

 

I have again checked the oil, water/coolant and they are still fine. The message came on again this morning after driving for around 10 minutes. The thermostat hadn’t even got to the half way line and shot right up to the max red line & told me to switch off which i did. I started the engine back up around 5 seconds after this message was shown and i had switched off (bad i know, but i was curious because it didn’t seem like the car was actually overheating) and the thermostat was back to just under half way where it originally was. It then drove fine again for around another half an hour, came on again, then disappeared after switching off and turning back on, and drove fine again. Is this a dodgy temperature sensor what needs replacing or the start of something else major 😣 

On some cars there is a wire that goes from temp sensor to temp gauge. On some the temp sensor connects to Ecu and ecu controls the gauge. On some of these the ecu can interpret signals wrongly and tell the car it is overheating when it is not. I do not know what type yours has

Hava a look at the reasons behind it.  Many You Tube videos will tell you the story.

It's not the electrical answer to your query I know, but just explains what happens to a rad, although your 2010 rad shouldn't be that knackered yet.

https://www.bing.com/videos/search?q=flush+your+cooling+system+-+the+proper+way&&view=detail&mid=3C7E3EE7F7692966FD923C7E3EE7F7692966FD92&&FORM=VRDGAR&ru=%2Fvideos%2Fsearch%3Fq%3Dflush%2Byour%2Bcooling%2Bsystem%2B-%2Bthe%2Bproper%2Bway%26qpvt%3Dflush%2Byour%2Bcooling%2Bsystem%2B-%2Bthe%2Bproper%2Bway%26FORM%3DVDRE