A8 blocked sunroof drain holes

[JohnF]

As the happy new owner of a rare 2005 SWB W12 I was miffed to find a wet seat and a small stream trickling down the inside A pillar trim after a recent torrential downpour. Easily fixed, I thought, as I pushed a thin plastic clothes line down the drain hole expecting it to appear above the lower door hinge as per a useful american U tubist. Not so! All I have where his line emerged is a round black plastic grommet, which when removed reveals... nothing much. My line went in about four feet, then just stopped. Same the other side - no drainage at all.
I searched under the wheel arches, no sign of outlets there, either. Has anyone else had this problem? Help, please!

[Micha_elD]

Hope you've fixed this by now - if not, and for anyone else with this problem, the best way to do this is to use something like a bicycle brake or gear wire, and push it down the holes you will have found near the front of the sunroof well. Don't force it, but when it hits a blockage, its probably blocked with grit, so twist the cable (in the right direction so it doesn't unravel itself), and it will eventually grind its way through the blockage. Might take a few minutes. if you just use pressure, you might dislodge the seal at the end of the pipe.

The pipes terminate behind the wheel cover inside the wheelarch, so you should suddenly see a trail of water appear from behind the wheel. You will need about 2m - maybe 6ft or so of wire to reach the end of the pipe.

[JohnF]

Thanks MichaelD, that's really helpful - I tried washing line but never thought of bike cables - just so happens I have some...

[green A8]

3.5/4.0mm plastic strimmer wire/ cable can be quite effective, when used with care. as can using a 100ml syringe full of hot water as a water pistol squirted down the front drains.

The biggest problem I've found with five A8's I've dealt with,mostly D2's, was that all of them bar one had blocked REAR drains. The front ones were fairly free flowing. Therin lies the problem, you can't see the rear drains from the top of the car. I fixed the problem two ways. Firstly, whip the rear bumper off dead easy to do no more than 5/10 mins or so. (Only done this on D2 models) locate the drain, you'll be surprised how much muck is hidden by your spotlessly clean bumper. The drain will be located beneath a rubber/plastic flap like object. Look for a damp area that's usually present. Probe the drain outlet with strimmer wire or sometimes a low pressure squirt from the hosepipe will dislodge the blockage, get ready to get wet if you're unlucky! I've had 2/3 Litres of water come out of each of the freshly unblocked drains.

If you do this and theres no improvement. Buy a cheap ebay type USB camera and use it with your laptop, get the smallest sized one you can. I tape my camera onto the tip of an old fishing rod and get to view the drains that way. If they're blocked I use the camera to guide in the strimmer wire or the syringe fitted with a long but fairly rigid pipe. It can take a while clearing from the top but it can be done. Take care though not to get too heavy handed if you dislodge the drain pipe from it's sunroof mounting you're looking at taking the headlining out to fix the problem. That said it's not too hard to drop the headlining on the D2 model. Don't know about the D3/4 cars.

[Micha_elD]

I don't think there are any rear drains on the D3.

Presumably the shape of the roof means it doesn't need them?

[guv.c]

Hi There,

I had this problem. So you are going to laugh when I tell you how much you have to take apart to get to the drains!

Wheels and wheel arch liners off first.

On the driver side, you have to completely remove the water bottle (PITA). This will allow you to see the drain point. See pic. It will be filled with soil (as mine was). Give it a clean and test it. Watch the water spurt out.

On the passenger side you should be able to see the drain once you prise away the arch liner.


I tried the clothes line too, it only fixes the issue temporarily. For a proper fix, the arch liners are the best bet.27366