Originally Posted by readheads

Here's what I know and remember, pretty much all sunroofs have a drain setup because perfect seals over all conditions are not realistic. I had a Honda Civic waaaayyyy back that had clogged sunroof drains (in hindsight) which would occasionally allow a waterfall on my back when I went into reverse out of my driveway at 7 AM on the way to work. NOT FUN ! One day (before internet) I decided I would just tear it apart until I found the source. It consisted of tearing out the interior head liners (+other stuff) to expose the drain lines which went from the sunroof trough to the back of the car and down to the car bottom. It was mucked up with leaves and stuff which caused a clog. Also, years later with my 2006 A6 MMI went on the blink and it turned out that the front cowel drains clogged up allowing an overfill condition which put water into the car under the floor rug (where the circuit board was) and shorted out the board. Both were caused by parking my car under the same damn tree in Northeast New Jersey weather where the combo of leaves and cold weather combined to muck up the drains. My garage is packed with my wife's giveaways which never seem to leave.

Bottomline: sunroofs need a place to drain, track that down and you will find the smoking gun, unless for some reason the sunroof is not closing all the way and for that I would look for a switch which gets engaged upon closure, it may be out of adjustment. Not sure where that is but a good manual should show you.

Edit: I attached 78 pages from the A8 manual on sunroofs. I downloaded the full suite for $29 last month and it has helped me figure out how to add USB outlets into my armrest storage compartment as well as mirror my Note5 to the MMI. My quick look shows you can do some searches in the pdf (Ctl-F) and you can find some relevant help. If you need any other help let me know (I am in NJ). I know I will need some someday also. Regards, Tom

BTW, does anyone know where a good site which lays out some of this stuff. I am a new owner of A8 (5 years on previous A6) and I would think there would be more of these solutions around, but I may be mistaken. WDYT ?

Also, I bought my 2011 A8L used and the dealer who maintained it told me the windshield had been replaced in the past but they couldn't tell why. It could be that also. As you might expect that would not be trivial.