stuffinder

Water is finding it's way to the area on the Driver/Left side of car. Yes I know there are threads pertaining to water retention issues in the C6 platform. Also, that the issue can occur primarily from three primary areas.
The most referenced are the Sunroof drains which often clog with leaf debris, etc. My car has had issues with SR previously and the PO had the entire SR assy. replaced. About a year ago, just before I purchased it the drivers side again became waterlogged wiping out BT module which causes MMI to crap out. He took it to the dealer who replaced the sunroof and they cleaned out his SR drains, replaced the BT module & declared it OK. I recently found the floorboard behind drivers seat(L) to be damp. My mechanic checked the SR drains and they seem to be working OK. A couple of days later the MMI went out and we pulled the carpet and found the underside wet & the BT module to be corroded externally. I pulled the BT module & put fiber optic loop in to get the MMI back. I dried that area well and dried out the BT module & got everything back up & running. In an effort to find out where the water is coming from I ran a stream of water from a garden hose into the area near the windshield wipers. It immediately ran out the drain hole near the center of the cowl area that we had already pulled & checked for obstructions so I thought that was OK. BUT this morning I pulled up the carpet again and can feel moistness that was not present before my garden hose attack. There are a bunch of links on various forums about SR,Cowl & AC drains but I'm still uncertain of the number of cowl drains in the plenum area behind the engine. If there is a second drain I'vv not yet found it! SO, MY QUESTION IS : HOW MANY & WHERE! TIA

raj99

Have you looked at this thread:
https://www.audiworld.com/forums/a6-.../#post24311818

There's also a water drain under the anti theft alarm located under the cowl.

royclark

The anti theft alarm located under the cowl is a mistake, it is the heater control valve.

On my 2009 A6 there are two drain holes in the plenum chamber.
One under the heater valves & the other under the brake reservoir.

raj99

Thanks for that Roy. I took it from another post and linked to the one you had...great diagrams BTW!

royclark

As a precaution you can remove the undertrays either side of the footwells then remove the rubber bungs in the floor pan so that if water does get in, it will run back out.
But don't go driving through any deep water with bungs removed.

stuffinder

Thanks for the input! When I get a chance we'll dig in and find that second drain & clear it out. I only saw one stream of water after hosing it down. The other threads were somewhat confusing but perhaps I'm just old & feeble!

life4sk8

Is your car is an avant or a sedan? I have an avant with a roof rack and 3 years ago I had a water problem. All the drain was clear... It was coming from the roof rack. I seal it with clear caulking and this solve my problem...

stuffinder

It's an Avant! Thanks for that tip, never thought of that. Was the headliner getting wet or did it show up in the floor like other leaks? TIA

life4sk8

The carpet was wet. I remove all the carpet and all the trim all way to the roof. I did a lot of test with my garden hose, bring the car to the car wash, I check all the drain with a snake cam... Could'nt find nothing. I poor water right in the sunroof and nothing. I was very disappointed. One day, my wife look at my car and said: did you look at your roof rack??? So I seal it and boom. Now it is always dry.

life4sk8

The headliner was never wet and all the trim too was never wet... And no moisture stain...