Water loss Omega A 2,0

Hello! I need advice from a few experts… I have a terrifying water loss with my omi. First I noticed when I was standing in front of a traffic light and the temp. shot up. At home then guck, and see… no more water in it. I unfortunately did not have a compensation tank. I filled up about 2.5l water (with frost protection). What repeated after about 500km. What should I do now? I can’t find a place where the water remains. So I go out of it that it burns, which then deuted to ZKD. *heul* He has only 124tsd down, was always driven with Mobil 1 0W40 with regular inspections. And I never kicked him in the cold condition. My FOH said I should expect about 600€ at ZKD. What can I do now to check myself to be sure that I don’t spend a lot of money for free? MfG Daniel