Hi

I have water leak on my Audi A3 1.4tfsi sportsback 2011 model, I've taken it to radiator centre and they did pressure test, Combustion leak test but they could not find anything wrong, but behind the manifold there are some residue which we are not sure if its coolent residue or not, We don't know if there is water that goes pass the manifold and if there is how does it pass there and what are the chances of the water coming from the manifold and how do I fix this issue?

I've also taken the car to Audi for a service and told them about the problem, they did a pressure test but they could not pick anything, Audi said I must bring there car again for them to do further test but I'm hopping I can get an answer before my next service.

Last week Friday I bought a new water cap thinking maybe it might be a coolant cab but its not because its still loosing water and we can not find where its leaking.

Please help, I don't know what to do any more.