Battery tray swimming pool.

**Finless** · 13-06-2019,04:06 PM

I have a 2003 A4 Avant Estate/ a B6(?) - 2.4ltr V6 petrol engine and I actually spotted water pouring into the passeger footwell (a bit like a tap being turned on just past dripping).

I had noticed damp carpets in the past and internet searches led me to believe that it could be a blocked drain or, at least, water being trapped in the battery tray. I'd say that about half a cup of water poured in.

I don't understand why it only leaks some of the time (don't get wet carpets every time it rains) but perhaps it is because it needs the water depth to be over a certain level? I had a quick look once the water had stopped pouring in and I could see that there was a water in the battery tray.

Are there any special things I need to know before I have a go 'at it'?

I have one problem because I can't find the radio code so I'll be trying to keep the battery connected by jump leads. I'm hoping to find the code because I can see my attempt as being troublesome / maybe not possible.

Does the water drain from the battery tray through a pipe or a hole? Is corrosion likely to be a problem?

As ever, thank you in advance, if you take the time to read this thread and are able to offer any advice. Sadly, finances dictate that I attemp the remedy myself so any advice will be much appreciated.

**kite** · 13-06-2019,04:09 PM

Remove the battery and tray, under the tray is a bung that clogs up, clean it, there is 1 under the brake servo too.

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**kite** · 13-06-2019,04:11 PM

Also, dry out your pax footwell, the CCM is in a plastic box under the carpet, if it gets wet it can cause all sorts of electrical issues.

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**Crasher** · 13-06-2019,04:19 PM

Take the pollen filter housing off and seal the base with Butyl sealing cord to replace the pathetic foam used. Take out the battery tray and poke the grommets clean BUT no not remove them, they are important. Make sure you clean the one under the servo.

**Gazwould** · 13-06-2019,06:22 PM

Plenum bungs .

And foam is just a skirt but the real seal perishes , new pollen filter housing complete is cheap .

**calum** · 14-06-2019,07:06 AM

If the radio is original to the car you won't need the code, on reconnection it will say "SAFE" then "LEARN" then it will work.
Here's a guide for the drain clearing.

Water drain cleaning. Unblock pipes A4 b6 - YouTube

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**Gazwould** · 14-06-2019,07:18 AM

Hmmm , that's poking the drains through to clear rather than the one go fix for life complete bung removal.

Considering the crap , bits of leaves , bugs , dust etc that collects there I'd do removal than having to remove battery and poke around again .

**Finless** · 17-06-2019,08:00 PM

Thanks all.

By unhappy coincidence my battery died today and I ended up having to change it so I cleared the blockages whilst changing it. Could they have put the retaining hex bolt in a more awkward place?

The radio came back to life w/out needing a code.

**Crasher** · 18-06-2019,10:30 AM

Originally Posted by Gazwould

Hmmm , that's poking the drains through to clear rather than the one go fix for life complete bung removal.

I have seen them still fill up with the bungs removed and the bungs are one way valves which when new and pliable, stop fumes from the engine bay being drawn into the heater intake.

**Traficant** · 06-11-2019,02:35 AM

Hi everyone. Probably it might not be the right place to post but I believe even so good old Google will lead someone struggling to find the issue over here. After all summer chasing the water into my drivers footwell on A6 C5, reading as much posts as i can, finally i have solved the mystery. As it was hot summer in UK and lots of A/C usage i have thought that is a drainage blockage. Did not make sense as it was driver’s side footwell. After that i got well flooded in a car wash and started to look for the issue properly. Drainages under battery of course were clogged but even after unblocking these out, i still had a wet carpet. So to cut the story short i ended up taking the glove box and under steering wheel access panel out. Got someone with a hose spraying water over the wind screen and saw a drip right over the steering shaft joint right next to the fire wall. In a good inspection i have found out that was a rubber bung/grommet fitted next to the servo. Since siliconed it well i drive with a dry socks even in the most heavy rains by now))))). Hope that can be a bit of a guide for those who can not sort the issue out easily as me. Please refer to pictures so you can easily figure out the location of that grommet i am talking about.