Since Christmas my 2.0 TDI Sportback (2005) - approx 55k miles - has been losing coolant. A couple of months ago I took the car to a local independant garage who carried out a pressure test & also looked for external leaks but found nothing. The coolant has recently required topping up every couple of weeks so I have had an Audi dealer investigate the problem and, again, nothing was revealed by the pressure test. Following further investigations by the dealer I have now been advised that the cylinder head requires replacement at a cost of £1,900. Just thought I would let you know that Audi will not accept any responsibility or acknowledgement that these models seemed to have a problem with the cylinder heads!