I own a 2007 A8 3.0 TDI, which I cherish. It is main dealer serviced (variable) and I have never added a drop of additional oil. I have noticed that the dipstick indicates it is usually overfilled (ie above the "max" indicator); and the oil is very black even though it is only about 6,000 miles since the last service. I am a little worried that the main dealer may be overfilling and/or may not be doing the oil change properly (eg not replacing the filter). In the old days, overfilling was harmful but I have no idea whether the colour should be black given this type of engine. I am going to come off the variable servicing regime so that the oil can be changed more quickly but am I being paranoid?