Hi, I have a 2004 A3 2.0 tdi Bkd engine with 170,000 miles. I have had a small coolant leak for the past two years which has got progressively worse, six months ago I brought it to my local mechanic who diagnosed I needed a new head gasket. He installed a new head gasket and also pressure tested the head ( found no leaks) but to my dismay the car continued to lose coolant. In the past month the leak has become so bad I have to top up the coolant ever second day, also the engine became very hard to start in the morning, when I try to start it the engine locks up and is very noisy. When it does start there is lots of white smoke everywhere.After some research I decided to change the egr cooler ( 330 euros) but this has not made any difference either. I dont know what to do next of where the coolant is leaking ( no signs of external leaks) I now open coolant expansion tank cap after long journeys to release pressure, this seem to help as not as much coolant seems to get into the cylinder for starting the following morning. Do I need a new engine? Did the pressure test not show up a leak on the cylinder head? Is there a crack in the engine block? Can you replace the engine block or is it better to get a new engine? Would k seal work? Any help, ideas would be greatly appreciated as I dont want to get rid of car as I still love driving it.