Hello Mat, thank you for your reply, I drove this morning my car and everything looks normal, the A/C is working and cooling, the ventilation propeller was not making any noise, but the weather is cool now.
The phenomenon happened once before when the car was standing in the sun for hours and there was very hot weather outside, I live in Tuscany, Italy where the weather can be very hot in July August.
What do you suggest to verify? I can go to the mechanic and ask him to check, but I have no idea what to ask.
Thank you again,