Aux water pump.
Thanks for the fast reply, I'll look for the pump first thing tonight.
The gurgling sound in my case stays also after a longer drive. In fact, just finding and maybe fixing the pump does not answer all my questions or issues. The main question should possibly be: where does the air come from, how does it enter my cooling system in the first place?
I'll find the pump tonight and have a look.
Again thanks for the fast answer and greets,