AudiTech 79,
I have a 2003 A6 same water on back passenger problem.Do I put the plug back in that is underneath the battery? The one with the fours slits in the bottom. I had heard I should leave it out. Thanks for your time.

Ben

 

I've an 2000 A4 but i too removed the piece while trying to address water in the rear drivers side (right hand side) footwell. I figured its not meant to be a plug but was only acting as one as it had gotten clogged with small leaves and other bits of muck, so with nothing there it should be more difficult to get clogged. The water draining through there end up falling onto the gearbox either with the 4 slit rubber piece in place or without it.

I say leave it out as it only seems to help flood the battery area.

Also make sure to unclog the other one on the other side. Both mine were clogged. Not sure if the A6 is the same as A4, but theres definatl 2 drain holes in mine. The other one is very difficult to see. Its sort of under some AC pipes or pipes for the heater.

 

had this problem in my allroad, removed battery and battery tray, blocked drain under this , got rid of plug problem gone with the water. Killed my allroad dead fried the transmission ecu.