Drainage Problems: Where is the Leak?

Hello fellow enthusiasts,
I can't find anything.
I have an Audi A6 4B station wagon, and when it rains, water leaks into the area where the battery is located and accumulates there.
Can someone tell me where the drain is located?

Thank you very much.
Best regards, Bastianna.

Under the battery. Remove the battery and take out the rubber stoppers.
It's a known issue with these vehicles.

Hi Michael,

"Thank you very much!"

Best regards,

Werner.
(Alias bastianna)

Here, I would like to follow up on something. Now that I have finally managed to get my 3B doors to seal properly (see: https://community.dieselschrauber.org/en/viewtopic.php?t=23783), but since I still drive more of a "wet habitat" than a car, I encountered the same problem last week, regardless of this thread.

After I had pushed the ice floes aside and removed the battery holder, which was practically underwater, I came across the original blind plug that was factory-installed.

Why does the VAG group install a plug at the lowest point as standard? Was it to prevent the hole from becoming blocked with leaves? I had to repeatedly reach inside and feel around with my hands – even though I was wearing gloves and my hands were cold – because of this.

It might be useful to compile a list of vehicles that have catalytic converters known to be targeted by thieves. On warmer days, or when the battery needs to be removed anyway, one could proactively remove the converter as a preventative measure.
Therefore, the following are affected:

- Audi A6 4B
- Passat 3B

How about the 3BG? Or the A4?

R.M. wrote:

What about the 3BG? Or the A4?

The 3BG doesn't have a drain plug. Neither does the Audi A4 8E, and I'm not exactly sure about the B5.

Hello everyone!

TDI-GTI-4-Motion wrote:

...regarding the B5, I don't know exactly now.

I am ABear!

"Stopfen" is located under the BKV (likely a specific system or organization), which I also had access to years ago.
Sometime during the winter, I opened the hood and thought I had an ice aquarium in the coolant reservoir (about 15 cm high!). I completely removed the drain valve and used a hairdryer to blow out any remaining water.
Since then, there have been no more problems.

Why this peculiar drain valve, or "drain plug," was designed and manufactured in this way remains a mystery to me as well. *laugh*

Best regards from Munich!

Quote:

Why this peculiar drain valve or "drain plug" was manufactured in this way remains "unclear" to me as well. *laugh*

I've also removed quite a few of these things because, firstly, they are difficult to access, and secondly, there's no guarantee that they will remain permeable.

Since the water reservoir in this case also partially decouples the engine compartment from the interior, I believe that the design of the drainages primarily serves noise reduction.

For example, a missing or open rubber grommet or cable passage in the mold can sometimes cause quite a loud noise.