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-   -   Water mystery in footwell (https://forum.a8parts.co.uk/showthread.php?t=13196)

Goran 10th July 2017 09:41 PM

Water mystery in footwell
 
I discovered a few weeks ago that my drivers side carpet is wet, not from above but from underneath.
I checked the orange drains either side of the centre console first. They were in good condition, dry and not blocked.
With dread I started searching for Botang's hole. However as the car is LHD I either don't have it, or if I do its on the passanger side so not relevant.

So I started with an experiment. I removed the carpet and loosened some of the sound deadening but couldn't see behind it properly as its huge and the top of it is pined to the bdy work somewhere up high behind the dash. I poured water down the windscreen then jumped into the footwell with a torch to see if any water came in. And sure enough it did but not where I expected, It dripped down from somewhere above to the left near the corner of the dasboard. The only possible entry points I could see from the Engine bay are a big rubber grommet with some wiring loom going into the cabin, a small orange rubber plug next to it, and the pedal box itself. If the butyl cord seal had failed that would be a real pain to re-seal the whole edge of the pedal box. Audi design of the hole in the firewall for the pedal box is not good, there is a flange around the hole allowing water to collect and sit above the bottom edge of the pedal box and body seal. I suspected this was the most likely entry point.
I got some black silicone sealant from Halfords (only 40g - doh!) and proceeded to seal the two grommets and the edge of the pedal box from the outside as best as I could. Cleaning and sealing the two grommets was easy, reaching in and sealing the edge of the pedal box, especially the bottom edge, was almost impossible. I did it somehow in the end with the help of a short length of silicone tubing, although I cant claim the seal is good because I could not reach the edge to clean it first. The best I could hope to do was fill in the channel created by the flange so at least there could be no standing water it would have to slide off.

HPsauce 10th July 2017 09:43 PM

What about your scuttle, is that dry?

As for Botang's hole I would imagine it's in the same place (your drivers side) but maybe actually used for something, unless it's an artefact of the manufacturing process.

Goran 10th July 2017 09:58 PM

Where is the scuttle? Is it above the two orange drain plugs either side of the centre console?

HPsauce 10th July 2017 10:08 PM

2 Attachment(s)
Under the bonnet, where water drains into from the windscreen. Access is largely blocked by the air intake to the HVAC unit.
It has a pair of big drains down either side of the transmission.
Mine gets blocked very easily from debris (leaves, seeds etc.) and overflows into the cabin.
The red circles on the attached pictures show plausible blockage points, mine is mostly the upper ones at the base of the tray (line drawing).

Goran 10th July 2017 10:09 PM

4 Attachment(s)
Here are pictures of this attempt to block the water ingress.

First picture is evidence of water dripping in.

http://forum.a8parts.co.uk/attachmen...1&d=1499721129

http://forum.a8parts.co.uk/attachmen...1&d=1499721129

http://forum.a8parts.co.uk/attachmen...1&d=1499721129

http://forum.a8parts.co.uk/attachmen...1&d=1499721129

Goran 10th July 2017 10:13 PM

Quote:

Originally Posted by HPsauce (Post 130133)
Under the bonnet, where water drains into from the windscreen. Access is largely blocked by the air intake to the HVAC unit.
It has a pair of big drains down either side of the transmission.
Mine gets blocked very easily from debris (leaves, seeds etc.) and overflows into the cabin.
The red circles on the attached pictures show plausible blockage points, mine is mostly the upper ones at the base of the tray (line drawing).

Thanks! I'll check that too but I did not see any standing water down there even when I pour a whole bucket down the windscreen. Also seems too low down to be related to my problem.

HPsauce 10th July 2017 10:21 PM

If you pour a bucket of water on the windscreen it should come out immediately under the car, both sides behind the engine.

Goran 10th July 2017 10:22 PM

3 Attachment(s)
I was happy for a week :rolleyes: Kept checking the carpet, it was dry, even after a little rain, but it was not a proper test. Then I washed the car yesterday, in the sun. And afterwards the carpet was wet, with warm water!
So today in despair and frustration I started digging in to the footwell dismantling any easily accessible trims to see exactly where its coming in. As it happens, from a most unexpected place!
I dug into enough sound deadening to be able to see the metal of the firewall and the mating joint of the pedal box. Then I poured a bucket down the windscreen. And sure enough it came in, to the extreme far left, from up above in the corner. Up there somewhere there is not just a single sheet of metal of the aluminium body, but a double-walled section a bit like a gently arched horizontal duct. And in the left corner before this double walked section has a square cut-out at the bottom. Water was coming in, like an Alien ;) inside this duct and dropping in from above!

With the sound deadening pushed out of the way I could also see the other side of the grommets in the corner, there were stains just below the big grommet for the wiring loom, water had got in via that in the past but not any more. Probably from when the wheel arch drain was blocked, I often had standing water there, so watch out for that one, worth sealing I think.

But unfortunately for me I am still none the wiser where the entry point is for my water ingress. I also suspected the lower left coolant hose going to the heat exchanger. It has a white oval seal and the lower seal is looking worse for wear, I thought maybe this seal goes through this double-wall section and may be letting water in, but I found it from the inside and it is dry with no stains. Then I sprayed water directly at just the lower seal with a hose but nothing came in.

Here is the offending 'duct'

Who is the most knowledgeable D2 genius who can solve this mystery?

http://forum.a8parts.co.uk/attachmen...1&d=1499722540

Zoomed out a bit

http://forum.a8parts.co.uk/attachmen...1&d=1499722764

http://forum.a8parts.co.uk/attachmen...1&d=1499723015

HPsauce 10th July 2017 10:57 PM

That "duct" looks like the main beam that I have seen that goes right across the car inside the dash structure.

Could Botang's hole be the leak?

Dezzy 11th July 2017 07:08 AM

Could well be Bontang's, Worth a dig around for reasurance.


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