Coolant Sensor Issues
If you have coolant sensor issues, this may be of interest.
Having checked mine it would seem that I was actually losing water. No puddles under the car (Well no more than usual & those are oil), no wet patches on engine or pipes & no sign of water inside the engine (Scum etc). I did notice that hot radiator smell on occasions so my suspicion is a defective expansion tank cap. Only £10 for a replacement so worth a punt.
I will let you know....