Changing the engine oil 2.7 TDI Audi A4 B7, A4 B8, Audi A5, Audi A6 C6, A6 C7, Audi A7, Audi A8 D3, A8 D4. Location of the filter and oil drain plug. The oil drain bolt and the filter element bolt are unscrewed counterclockwise. The oil volume is approximately 7 liters.