Information Got water in the battery compartment - these are the culprits!!!

Birchall

Dick Chown Award 2016
Hi,

I have just received the two vents I ordered from CreweAudi (thanks)(

Many people might have a "fishtank" instead of a battery compartment and so I thought it might help to show the cause.

Firstly the vents are behind the rear bumper and it has to come off to repair/replace the vents.

This is where they are shown by the red square (they are on either side at the rear)

WHite shell rear vent.jpg

This is what the vents look like off the car
This is in the normal position and the grey inside the squares is very flimsy plastic that keeps condensation out but allows air OUT. If you have ever owned an old style VW Beetle, you will know that the doors are tricky to slam unless you open the window to let the air rush out. This design means that you can slam the doors and the air can escape and yet it does not let water / moist air, IN.

Vents 2.jpg

When turned upside down you can see that the flaps flop open (they are VERY flimsy plastic much like the thick material used on heavy duty bin bags / rubble sacks.
Vents 3.jpg

This is the shot from the "inside" view of the vents
Vents 1.jpg

The main reason for the leak is the (equally flimsy) seal tends to get dislodged when you have a rear shunt or if the bumper has been replaced for any reason. They clip into the body and the clips are not fantastic.
Sometimes the vent cracks.

The temptation is to drill a hole in the battery tray floor, but that doesn't work because there are several low spots and so you would need several holes, and in comes the moisture again.

The two vents cost me £42 from Crewe Audi and much better than trying to repair the existing ones Part number 4A0-819-181-A. The sight of the compartment filling up again after all of that work is such that the £42 is money well spent!

I have asked for this to be added to the "How To" Index thread for future members to find (Well worth a read if you haven't discovered it yet)

A list of some of the "How To's" and useful threads


Steve B
 
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Do you have the part number ?

Hi,

Just dug the wrapper out of the bin!

4A0-819-181-A (I assume that is for one of these)

They are used across the whole VW Audi range (hence the 4A0 and not 8Z0) so should be easy to get

Steve B
 
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will give this a look! I'm hoping it's down to the wind deflectors i'd put on the car messing up drainage perhaps.
 
4A is the designation for the old Audi 100 from the early 90s.

If you have water in the boot The Stable, it's deffo from these vents, nothing to do with wind deflectors. Bumper off and new seals is the way to go. I've seen loads of attempted repairs and nothing works for more than a couple of months.
 
4A is the designation for the old Audi 100 from the early 90s.

If you have water in the boot The Stable, it's deffo from these vents, nothing to do with wind deflectors. Bumper off and new seals is the way to go. I've seen loads of attempted repairs and nothing works for more than a couple of months.

Cheers!

I'm sorry if this is a stupid question, but is this looking like a case of replacing the vents as mentioned above or are the seals different? I just can't understand how the seals would cause such an amount of water to come in that it would make the back seats wet. However, It is not uncommon for me to not understand things that just ARE, so if the vents/seals are what needs to replaced i'm on it! I'll get this sorted sharpish when we get a dry day!
 
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In my previous post, the word seal and vent are interchangeable. The vent assembly has a lightweight neoprene-like seal around it and attached (you can't take it off) and so when I said new seals are the way to go, I meant entire new vent assemblies.
 
Cheers!

I'm sorry if this is a stupid question, but is this looking like a case of replacing the vents as mentioned above or are the seals different? I just can't understand how the seals would cause such an amount of water to come in that it would make the back seats wet. However, It is not uncommon for me to not understand things that just ARE, so if the vents/seals are what needs to replaced i'm on it! I'll get this sorted sharpish when we get a dry day!

The rear vents behind the bumper will only make the rear seats wet due to the condensation caused by all of that water in the car.
The inside of the windows normally get soaked with condensation too most cold mornings.

If you have the sunroof (OSS) on your car and the seats are soaking wet then that is likely to be the cause of wet seats, but it sounds like your rear vents are causing the battery compartment to fill up.
If the seals have failed on the vents all of the water runs down from the roof at each rear cornet will trickle through the seals and into the boot.

Steve B
 
Bit of investigation later...
Dried the car out, took it for a nice drive to Amersham for a job. Raining all the time... Got back and the boot was damp again. not so much of the water in the battery compartment but when I lifted the rear seats up there was water underneath them and silica gel pouches under there too. I think there is a longer problem here for me, there is also cables gaffe taped down under there which i'm not sure what is either.

Whats the Black circle manhole type cover under the seats do?

Anyway! will order the seals tomorrow from Crewe and get that done as soon as I can. no point in sorting the boot out until it's all dry!
 
That is the cover that gives you access to the fuel pump / sender.

The rear seals will only cause the water in the battery compartment, so if you have water under the seats? that is a new one on me.

Leaking sunroofs can make the top of the seats wet and the headlining, but under the seats????

Steve B
 
I seem to recall that there are some wires taped down on mine too. Likely nothing to worry about and a means of securing them from factory.
 
I had water in boot and damp carpet under rear seats extending to carpet in rear foot Wells.
Bumper off vents replaced and sealed never had any more problems and that's been 2 years now.
And I do have OSS.
 
That is the cover that gives you access to the fuel pump / sender.

The rear seals will only cause the water in the battery compartment, so if you have water under the seats? that is a new one on me.

Leaking sunroofs can make the top of the seats wet and the headlining, but under the seats????

Steve B

It’s not so much water. More condensation. It’s all just very damp.
35468a35c6f03b750b51db447652345d.jpg


I’ll definitely change the vents give it a dry out and see where it goes from there. Perhaps I should have a look at gutters after that. If it comes back.


Sent from my iPhone using Tapatalk
 
Ah yes, condensation. That is why.

Often the only time people realise that they have a problem is due to the smell of stale water and condensation everywhere, especially on the inside of any glass, but also on other interior surfaces.

So you should be fine once you have fitted the new ones. It has always worked for me (I have had to do it on three of our A2s. (Or should I say I have paid someone to do it!!!

Steve B
 
It’s not so much water. More condensation. It’s all just very damp.
35468a35c6f03b750b51db447652345d.jpg


I’ll definitely change the vents give it a dry out and see where it goes from there. Perhaps I should have a look at gutters after that. If it comes back.


Sent from my iPhone using Tapatalk
That's exactly the same as I had replacement and sealing the vents cured it.
 
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