What you say is correct, but the service unit claims that everything is ok, the cooling system is tight without leaks, and the losses result from evaporation. In this case, I will send an email to Skoda Europe and Skoda Czech Republic, in which I will explain the situation, and ask for their point of view.

Your service unit is telling you complete nonsense, the cooling system is a sealed system - there should be no evaporation provided the pressure holds and there are no leaks!

Have you tried replacing the pressure cap on the expansion tank?

1 hour ago, Warrior193 said:

Unitatea ta de service îți spune prostii complete, sistemul de răcire este un sistem etanș - nu ar trebui să existe evaporare, cu condiția ca presiunea să se mențină și să nu existe scurgeri!

Ai încercat să schimbi capacul de presiune de la vasul de expansiune?

I understand perfectly what you are saying. Regarding your question, the answer is no.

3 hours ago, Tipitip said:

I understand perfectly what you are saying. Regarding your question, the answer is no.

I'd suggest purchasing a OEM replacement pressure cap to see if that resolves the coolant losses.