Help Help!! Audi 80 B3 cooling tank running empty!!!

Hello, I have a very big problem. With my Audi 80 B3 Bj88, 1.8l , 90Ps the water tank runs empty within seconds. I can only say something like where it comes out and to the right of the carburetor so, near the cyinder head. Exactly I can’t see it because of the carburetor and air filter box that is in the way. My question now: Where could it come from? What kind of hoses might be running for long? What do I have to dismantle to get there? What do I have to bear in mind (gass) he expand ect) ? I hope you can help me quickly! Thank you in advance! Greetings Sascha