Why do I have to add coolant to 2010 VW Eos? Where is the leak?

Unfortunately - here online - we can perform the required *hands-on* inspection to determine the actual leak source.. I have had some success with this, on various vehicles, by leaving the tester attached with pressure on the system overnight - then checking for evidence of the leak next morning.. Of course this requires leaving the vehicle with the repair facility for a while. Good luck!