so it snowed a lot, and my car was sitting for a few days covered in snow, it rained yesterday and melted the snow, i took the car out and my passenger side footwell is filled with water, the rubber mats had alot and the carpet is soaked, should i be worried this can damage anything under the mat and what can i do to address this.
This is a copy and paste from another forum…
Checking, cleaning, removing and installing plenum chamber water drain
Note
t Drainage of water out of plenum chamber may be impaired by deposits such as leaves and pine needles accumulating in the water drains. If the vehicle is then driven through a car wash or in the event of heavy rainfall, the water level in the plenum chamber will rise and water ingress via the fresh-air intake -A- into the air intake unit -B-.
t The water drain hose -C- is intended to discharge the small amounts of water entering the air intake unit via the fresh-air intake in normal operation.
t The water drains via the water drain hose -C- out of the plenum chamber (via connection -D-) into the transmission tunnel in the area behind the noise and heat insulation mat (a hole is provided specifically for this in the bottom of the plenum chamber).
t A plastic element -D- for reducing the cross-section is inserted in the water drain hose -C-. If plastic element -D- is not fitted, noise may occur depending on fresh-air blower -V2- speed.
http://i1263.photobucket.com/albums/ii626/royclark/waterdrain1.png
The water drain socket -C- is accessible after removing the alarm horn -H12- of the anti-theft alarm -B-. The water drain socket -D- is not accessible with the brake servo and air intake unit -A- in position.
t If the water drain sockets -C- and -D- are clogged with leaves and pine needles, the drains may freeze up in winter and prevent water drainage. After driving a short distance, the heat emitted by the engine and exhaust system causes the ice in the drains to thaw again. It is possible that the water will have drained off from the plenum chamber again by the time the vehicle arrives at the workshop.
t The water drain socket -C- can be cleaned for example after removing the alarm horn -H12- of the anti-theft alarm -B- (removing alarm horn -H12-
t Coarse dirt can be removed from the water drain socket -D- using a commercially available flexible gripping tool for example. Fine deposits and sludge can be removed for example using a thin water hose or a pressure-feed spray gun -V.A.G 1538- and a nylon probe -V.A.G 1538/2-.
t If one of the two water drain sockets -C- or -D- is blocked and there are leaves, for example, in the plenum chamber, remove coarse dirt from the area beneath the air intake unit using a commercially available flexible gripping tool for instance. Fine deposits and sludge can be removed for example using a thin water hose or a pressure-feed spray gun -V.A.G 1538- and a nylon probe -V.A.G 1538/2-.
t To stop water from the plenum chamber flowing via the water drain hose -E- into the air intake unit, the hose ends in the area behind the noise and heat insulation mat in the transmission tunnel.
http://i1263.photobucket.com/albums/ii626/royclark/waterdrain2.png
Removing and installing alarm horn -H12-
Fitting location: in plenum chamber (front) between electronics box (right-side) and blower box.
Removing
– Switch off ignition and take out ignition key.
– Pull off rubber seal -1- for plenum chamber cover.
– Remove plenum chamber cover -2-.
http://i1263.photobucket.com/albums/ii626/royclark/alarmhorn1.png
http://i1263.photobucket.com/albums/ii626/royclark/alarmhorn2.png
– Unscrew nut -2- for alarm horn -H12-.
– Unscrew nut -3- for retainer -1-.
– Remove bracket from blower box -arrow- and take out retainer from plenum chamber.
– Unplug electrical connector and remove alarm horn -H12- from plenum chamber.
Installing
Installation is carried out in the reverse order; note the following:
– Note bonded rubber bush for blower box when installing bracket.
Tightening torques
Component Nm
Alarm horn -H12- to bracket 5
Bracket to body 7
Lots more info in the following thread…
http://www.audiworld.com/forums/a6-s6-c6-platform-discussion-58/please-help-water-footwells-2828279/
http://www.audiworld.com/forums/a6-s6-c6-platform-discussion-58/please-help-water-footwells-2828279/#post24323897
First, find the source of the problem, as outlined above.
On the C5s, the TCU was under the passenger side mat. They would get fried when you had this type of leak.
The TCU on the C6 S6 is in the transmission (IIRC) so, no worries there.
I dont know if there are any other electronics under the mat. But, if the water gets high enough then you can fry the electronics for your power seat.
I would say, fix the problem and then get the car as dry as possible. After that, if there is a problem with any of the electronics, then you will probably recognize the symptoms pretty easily (e.g. seat wont move).
Let me know if you cant find the leak after following the stuff in that thread.
is my engine bay the same as the ones pictured, those looked to be a6, i think i saw this diagram before and tried it but couldnt figure out what i was looking at, this happened before and i used an air hose with a blower and got a lot of leaves out but its happened again and its scaring me.
Have you changed your polin filter or air cab filter.
Take out the kick panel and it might make sense to pull the glove box out. That will show the drain lines going through the car. It should be a very obvious green color.
After that make sure to pull the seat all the way back and pull up the carpet. Make sure there isn’t standing water under the carpets. I think that’s where your Bluetooth module is a long with a few other things.
had this exact thing happen to me over a year ago and it was a $300 fix with the dealer. something about a clogged drain in the sunroof area… hope this helps.
thanks for the forum owner for this fantastic site!
Welcome nice to hear from more S6 guys. This seems like it’s something that is coming to be an issue with the S6.
is this something i can do myself, i work at a shop and have some technical knowledge, do i just open the sunroof and look at the rails and look for the drain hose or something.
Good info here. Ill be following along so that I can add this to the Info Dump.
Pat, please let me know when this is resolved. Any pics along the way would be great too.
Ok went to clear the sunroof drains, put a blower through the left side drain nothing came out, put it on the passenger side where the water was getting in and about 2 cups of water came out the other side of the drain and some tiny rocks, not sure if this was causing the leakage in the car but it rained all night and my passenger side didnt accumulate more water, now i just have to dry the flooring and hope its fixed, i will take some pics and post.
That sounds like good news.
Thanks for the update.
Looking forward to pics
Pat that’s great. I think posting pictures will really help lots of people. Seeing the drain location on a graph isn’t anywhere near as good seeing in on the actual car.
Will take some pics tonight, i had to move this weekend, i only cleared the sunroof drains, particularly the passenger side and it rained all weekend and no water. it seemed to have worked, still need to clear the drains by the cowl to be safe.
wow… one of my posts helped a fellow S6 owner. awesome! 
That is what AudiRevolution is all about Nice work!