I suspect that the water radiator tank doesn't give water to the radiator, because is full but the light "add coolant" and the beep come up.
But it do it only when the engine is cold for about the first minute in the morning.
The radiator cap is leaking a little bit when the engine is hot, i replaced it with a new one with the spring set for 0.9 BAR, is that correct???

Thanks guys.
Happy Holiday
Pietro De Lorenzo

 

I hope Im not right but it sounds like you either have a larger leak than you think and or you have the first symptoms of coolant seal failure. If I were you, and from the sound of it I was about 10 months ago, I would do a seach on the forum for coolant seal failue and the symptoms and possible solutions aside from getting your motor rebuilt. . . . Good Luck!