Yesterday while on a quick drive to the get gas - the engine temperature warning appeared for the first time - I saw the engine temp. move from a steady 194F to 220F rapidly. I pulled over and waited for the engine to cool - but did check to see if there was an obvious sign of mechanical failure - I did not notice any coolant leak - or smell - after about 30 minutes - I made the trip back home - with the engine again being stable at 194 for a few minutes and then shooting back into the 220 range and I am certain higher if it was not a quick trip back home. I checked the coolant reservoir and noticed that it was a bit low - towards the bottom of the low level but not far from empty - so I refilled with distilled water back to the Max level, but the car still showed the same issue again even after this action. Wanted to ask if there was anything else I should DIY check? I already have an appointment for Monday to bring it in, but if there is something that I am missing that is more obvious - I would rather just solve it myself - but when it comes to engine temp. I do not want to risk this - outside of an off A/C software issue - never had any other trouble with it, but the coolant temp. spike is an interesting one.

 

Typically if the coolant is low enough to cause any issues the low coolant warning will come up well before the temperature spikes. This sounds more like the temperature sensor might be going out or on its way out causing intermittent failure. Good luck