[PeteD]

My 2015 V6 F=Type coolant reservoir light comes on level is down a bit, no leaks no water in oil top it up couple days later lights on again. Car runs fine any suggestion (Pressure Cap?)

 

[jhcavalla]

There is a known failure mode in plastic coolant pipes running under the supercharger. You might try googling this. AFAIK, the plastic pipes can fail suddenly.