Louis, Ive got an A4 1.8t sport 2003 with 60000 on. The other day my oil warning symbol came on in the main computer display( not the little round light). I checked the oil level, everything was ok but i was worried i was leaking oil. Took car to Audi main dealer who could not find leak and suggested that oil level may have just dropped a bit low. Again today oil warning light came on. Reading many blogs people are talking about all sorts of things from, oil sludge build up, oil pressure switch, wrong grade oil, blocked oil gauze,etc. Ive only just noticed that the inside of the filler cap area is very dry and smoulders a liitle smoke when opened after engine is hot ?? also when engine is ticking over and cap is off you can actually feel air being pumped out of the filler cap area. Not sure whats happening and if either are nornal but will hopefully find out Monday when i take car back to Audi. Will update this blog asap. Neal.