Battery Compartment Flooded!

Posted: Mon Apr 13, 2009 7:49 pm

After driving in the heavy rain at the weekend I noticed the carpet in the front passenger footwell of my A6 was wet in the corner. After feeling up behind the glovebox the insulation foam was also wet.

I opened up the bonnet and took off the cowl panel at the back of the engine bay covering the battery and pollen filter area to see if I could see an obvious leak.

What I found was the whole area under my battery was full of water! Shock

The level was right up to just below the battery itself, probably about an inch and a half of water. I had been driving around quite a lot on country lanes and quite often water was spraying up over the front wings from large puddles at the side of the roads. So I think that is how so much water got in in the first place.

As I was away on holiday at the time, after much dunking and wringing I managed to soak all the water out with an absorbent sheet I had in the boot.

I guess the drain holes must be well and truly blocked. and when cornering the water was sloshing about and getting in through the pollen filter, as that was wet in one corner. Taking out the filter I could see a trickle of water in the corner of the duct.

Fortunately not too much water got into the car, but I need to make sure it doesn't happen again.

I found this post detailing where the drain plugs are:

http://forums.audiworld.com/showthread.php?p=15351602

The annoying thing is I only replaced my battery a month or so ago, and I didn't think to clear the drain holes then as I'd had no problems with water before.

My reluctance is that fitting the new battery was a bit of a nightmare. It being such a tight fit getting it in past the top of the chamber.

I have read that you are supposed to remove the lower plastic passenger windshield cover after taking off the wiper arms to make life easier.
But I couldn't see any retaining screws on mine and it seemed fixed to the windscreen.

So really my questions are, can I access the drain plugs without removing the battery?

If not, does anyone have any tips to make the battery removal easier?

Posted: Mon Apr 13, 2009 8:04 pm

I can't answer your question sorry, but I can add that it is imperative to do! I know a guy near me with an A6 1.9TDi who this happened to and the water got through the bulkhead near the brake servo I believe, and was taken into the engine by the air intake Shocked

Posted: Mon Apr 13, 2009 8:58 pm

My front & Rear passenger footwells filled up before i realised the problem...Remove the Battery & clear the problem.....Too many cables under the carpets to contemplate....... Wink

Posted: Mon Apr 13, 2009 9:26 pm

Not uncommon - most likely the drain holes at the side of the scuttle cover (through the inner wing) is blocked with leaves, moss and all the other muck that finds it's way down there. Water then builds up and seeps in through the grommets. Confused

Newbie Joined: Apr 16, 2009 Posts: 3

My A6 (4 years old) had the same problem and AUDI UK and my Local dealer Paid fully to repair the problem clean the carpets, new pollen filter and housing new ECU too.... i was so impressed with AUDI UK, I've ditch my land Rover to buy a second A6... PS it was the pollen filter housing which was letting water in, I'm told its common with AUDI and VW's. sorry not much help i guess but just my 2 cents..
Rob

Posted: Thu Apr 16, 2009 8:33 pm

every 2 cents help... Laughing

Newbie Joined: Mar 14, 2009 Posts: 17 Location: Sussex

If its anything like my A4 which i suspect it is then its so much easier to remove the battery. On mine there is a bracket on the left side of the battery, this keeps the battery in the tray, undo the bolt that holds this and then you should be able to slide the battery out with a bit of shuffling !

The battery sits on a tray and the drain hole is directly under this so would be a little difficult to get to without taking it all out. The other drain hole is just under the brake servo, you can get to it, just - with something like a car aerial and then push down the drain hole.

Just make sure you have a decent socket set with a extendable bar to remove the bolts that hold the tray in place, if i remember rightly, i think there is about 4 bolts holding the tray in place.

The lower black plastic windshield cover has a few black screws which sit flush with the cover and you only need to turn them a tiny bit to release them from the catch underneath.

Take your time and you will be fine Smile

Posted: Sat Apr 18, 2009 9:30 pm

Got my drain plugs unblocked today. Very Happy

The battery compartment was flooded again, after sitting for a few days parked.

Fortunately the water just sitting there wasn't leaking into the inside of the car. But was getting in when cornering , making all the water rush towards the pollen filter.

But I am suprised it filled up over a few days, we have had some rain, but I wouldn't have thought that much should run into that area, but it did!

Anyway getting the battery out again wasn't too bad after I found this write up:

http://xyrotr1.com/misc/passat_tech/unblocking%20passat%20drain%20holes.pdf

The layout of the A6 would appear to be identical to a Passat.

Once I found you could unclip the wiring that runs along the front of the battery compartment and move it out of the way, lifting the battery out and removing the tray to access the drain plugs was a doddle. No need to remove and windshield trim at all.

The two drain plugs were totally blocked with mud, not suprising I guess as the car is now 10 years old and I bet that was the first time they've been cleaned!

Here are a few pics:

Battery Compartment Full of Water:
http://www.flickr.com/photos/37500740@N05/3453871236/

Battery Compartment Empty After Removing Blocked Drain Plug:
http://www.flickr.com/photos/37500740@N05/3453871548/

One Of the Blocked Drain plugs:
http://www.flickr.com/photos/37500740@N05/3453871358/in/photostream/

Posted: Sat Apr 18, 2009 10:16 pm

A job well done there sir! Wink

Inexperienced Joined: Aug 25, 2004 Posts: 20

A very common problem with the A6 and the Passat which is based on the same model.

I found a very good write up on how to do this with pictures at http://www.weirdlittlebiscuit.com/passat/leak/index.htm, which appears to be down at the moment, but usually reappears later.

You might also want to check under your carpet for water - the Convenience Module lives under there, and if that gets wet and corrodes, it's expensive to replace and controls all the central locking etc.

Posted: Mon Apr 20, 2009 6:11 pm

Thankfully not too much water found its way into the car.

Only had a small damp patch on the top surface of the carpet in the left hand side of the front passenger footwell, and the foam insulation stuck up behind the glove box was wet.

No water seems to have got down behind the carpets.

I dried it all up thoroughly and took the glovebox out to wipe out behind that.

So hopefully now all is well.

The write up you mention in the link above, is the same as the one I found as a pdf file, which I linked to in my earlier post.

A very useful and comprehnsive guide indeed! My gratitude to the author.

Audi Nut Joined: May 19, 2007 Posts: 50

I had the same problem, its was the two drain holes in the centre that were blocked with debris they are a bitch to get at as they are over the gearbox.