Hi, i have a problem my car is 1.9 jtd 8v. Only when the weather is hot above 25 celsius and the sun shine wont start first. The screen appeared "Excessive radiator fluid temperature, stop and switch off engine". The second start was all right the car is goood. When car is running all ok nothing messsge.

Do the homework before posting another thread like this. You are basically spamming the forum.
Search (and peep at sticky threads and Guides): https://www.fiatforum.com/grande-punto/318839-electrical-gremlin-thread.html
Sounds like bad coolant temperature sensor, wiring, ground/earthing.