Originally Posted by q5q7
Do you have a pic to inform me where it is...?
The blue cap in the upper right of the photo of the 3.0T engine bay). This is the A7 but the A6 is very similar. It's been in that area for years on all of my Audis. Not ideal but not all that difficult to access either. As said, you can use a funnel if you want to be tidy. I've gotten pretty good at aiming the spout over the opening w/o too much over-spill.