Water ingress

[muffster]

Evening folks,
Sorry but its another question about water ingress. I've spent ages searching this forum but cant find the solution.
Its a 2008 A4 Avant. I've got water in both driver & passenger foot wells. Was just damp at first but now quite wet, not sure if it is from the heavy rain recently.
So far ive had the front plastic panel out, the one in front of the wipers and cleaned all the leaves etc out with an air line. It wasn't too bad but i couldn't actually locate where the drain holes are.
Its got a panoramic roof so ive cleaned out the sunroof drains and watched the water run out by the A pillars. Also just had the glove box out, it has some evidence of water marks around the frame of the glovebox but it was all dry up there. Also saw that the AC drain was still connected.
The wet patches are on the flat parts of the foot wells, so behind the pedals and up the sides is dry. The plastic trim on the sills and carpet up to the sills is dry. Under the seats are dry.
So, where is the water coming from? Im stumped!
Anyone else had this, how did you solve it please?

Many thanks.

[spartacus 68]

The bulkhead plenum area is the usual culprit. The passenger side drain plug you should be able reach, but the driver's side one has brake servo covering access. Double check with a torch to see there no residual water pooling there. I used a little washing up detergent in piping hot water and a long handle paint brush to clean surfaces so water would drain properly. In the end I removed the passenger side rubber star-shaped drain grommet as it's likely to block again. Run hose in it to clear.

As soon as you mentioned panoramic sunroof I thought cassette. I had a similar problem on my B8.5 Allroad and eventually traced leak to there. The sunroof mechanism is mounted in a plastic sunroof cassette, it's that - that I found leaking.

Before attempting this job, then at least take off A pillar trim off (details further on), pour warm water on roof and see if water drips appear at headlining where A pillar trim attaches as that will confirm before you start the following repair.

To access, remove power to the battery and leave for 30 minutes. There's front, side and A pillar airbags, so don't attempt without disconnecting. The passenger glovebox is easier out of the way and if you've removed already, then you know how it comes off. Actually the clue is there as this is where water drops down from the A pillar trim onto the plastic trim blow and then the carpet.

Next, remove interior grab handles at the front. You need a special hook tool to remove plastic wedge once screws are out, but you can improvise. Now interior passenger side and driver's sun visors. Next the rubber door weather surrounds, paying special attention as to how they fit. Lastly the A pillar trim. Under the plastic airbag badge is a screw which needs to be removed.

If it's like mine, the water was dripping from the cassette at the front, onto the roof lining and then down the A pillar trim. The A pillar trim is plastic and fabric covered so you're never going to see damp patches appear.

With everything off you can access under roof lining. Be careful and don't haul. You're going to refit so don't fully pull down or away from front of sunroof, just enough to access, see drip and hopefully repair. Obviously, choose a decent day to do this, plenty light and give yourself time to do. This is a driveway or garage type job.

You can test with warm water and run into the channel of the open sunroof. Most will drain through sunroof A pillar drains and exit at the door hinges, but chances are you'll see a drip start at the cassette. To fix, get some Sikaflex 291. This stuff comes in black and white and is basically a waterproof cauk and sealant, but is top specification for marine use. Dry off area where drip appears and liberally apply Sikaflex and smooth off to around a couple of inches in diameter. Trust me, you don't want to do this job again. It cures quite quickly, so you can start reassembling within an hour.

Once everything is reassembled, look at sunroof from above. The drain channel that runs around the sunroof may even have a hairline crack in it. You can choose to run a little Sikaflex here too. I used a strip of Gorilla tape to seal. Leave for 24 hours before washing car and avoid Karcher type pressure washer near the sunroof, other than over it, not directly on top if that makes sense.

Connect battery again, hopefully no airbag lights. I did have one, but cleared with VCDS software. Anyway, best of luck and let us know how you get on.

[muffster]

Thanks for the reply Spartacus, sounds very comprehensive. Ill have a crack at it next weekend and report back.

[muffster]

Bit of an update.
I managed to find the other drain hole which is underneath the brake servo. It was blocked up, cleaned it out and hoped it would cure it. The rain has been heavy over the last 2 days and the water in both footwells has returned.
My washer bottle is empty and I haven't been using the aircon.
This time the carpets are wet just below the plastic trim/kickplate areas in both footwells, the bits of trim that go up the sides.
Any ideas if this will be the sunroof or coming in from the firewall areas?
Could it be the drain holes in the bottom of the doors?


Many thanks.

[spartacus 68]

You can rule out the sunroof by removing the A pillar trims and trying water on the roof. Before doing this, disconnect the battery for 30 minutes, then the A piller trim with airbags underneath, hence caution. As I said, the water runs from the roof lining down the A pillar trim (which is plastic) and onto the carpet.

Another option is to use plastic bin liner in gap between door hinge and footwell trim and see if water pools there. Once you can see drips you can trace back.

[muffster]

Progress at last.
I've got some of the interior trim stripped out so i can see where the leak would come it. And it has after some recent rain.
So, spartacus, it is exactly as you have described above. The headliner is wet around the grab handle and after pulled the liner down a little it is wet and i can see the blue tube and the white connector which i believe could be the problem.
My issue now is a cant get far enough inside the headliner to get to the tube. The grab handle will not come out. You mentioned above about screw for these grab handles but n my 2008 A4 there aren't any. Apparently they pull down with a 'L' shaped/right angle type trim tool which with a downward motion pops the handles form their housing in the roof. I tried this and only managed to break a small piece of plastic trim from the handle.
Now this is what is stopping me from sealing up the drain tube. Any ideas on how to get the handle out please?

Thank you.