Unblocking drains DEFINITIVE THREAD

[Green Goblin]

Right then, car has just passed the MOT for another year which is all good, however I’ve got the car booked in for Friday because the passenger carpet was damp and there’s a damp smell in the car. The foam underneath was quite wet but not utterly sodden so may have just caught it before I get a swimming pool.

So, it looks like one or more of my drains is blocked. I’ve looked at the common faults thread on here and found the Quattroworld link detailing the drains: https://forums.quattroworld.com/a8/msgs/18945.phtml

Forgetting Botang’s hole, how many actual drain points are there? Exactly where are they? And what colour are they? Are there 5, 6, 7, 8 drain points??? And which nipples can be totally removed and which ones need to stay (and just be cleaned). I ask this because there doesn’t appear to be a DIFINITIVE drains guide anywhere. Yeah, sure, I’ve searched exhaustively on here and found myriad posts about water ingress but they’re all referring to assorted and differing drains.

Realistically, how much labour would checking/unblocking all the drains cost?

I wanna nip this in the bud (or is that nip this in the nipple, if you will..). Maybe get a nippleectamy or 3 lol. However, my mental health hasn’t been fantastic recently, it’s freezing cold and damp and I don’t have a nice warm garage either - hence booking it in.

My local guy is pretty good but I wanna go in there armed with the knowledge of all the points so he can do the work. I wish to high heaven that I lived nearer to D2Doctor or Unit20 or the like but unfortunately I’m nowhere near - I’ve used this chap a couple of times and he’s actually pretty good. He sorted a tricky problem on my other car and didn’t charge me the earth to fix it.

Forgive all the questions - but there is unclear info - for example in the Quattroworld post above, it mentions more than 2 sunroof drains, front and rear of the vehicle - so does that mean there are 4 for the sunroof??? You get the idea why I’m asking.

If there isn’t a definitive drains thread then I really do think it’s high time there is one, i.e. this thread - because blocked drains on this car are are so ridiculously common and problematic.

Thanks chaps and chapesses

[HPsauce]

I can't give a definitive answer on exactly how many drains there are (or additional leak points such as Botang's hole, boot grommets, rear light clusters etc.) but I can say that they never, ever go away.

Whatever you do something, somehow will find a way to block the drain and cause problems, so be prepared to regularly clear them.

I'll stick what little I know on my next post for others to then copy/edit to accumulate a single list in one post.

For the record I have no issues with sunroof drains or Botang's hole. But I never ever open my sunroof......

[HPsauce]

List of drains and water ingress points (please copy and add/expand/explain):

1. Orange drains from aircon condenser tray, one each side of the transmission tunnel behind interior trim (which needs care and knowledge to get out undamaged)
2. Scuttle drains under windscreen scuttle panel. Easily blocked by leaves, difficult to get at. IMHO it's not really the big nipples that are the problem, but higher up in the tray.
3. Sunroof drains
4. Boot cable grommets, especially on right side. MJ has a solution.
5. Seals around rear light cluster in boot lid
6. Rear numberplate (not sure about this one, but I've seen people seal there)
7. Small drains under bonnet, either side close to the wing panels.

[steamship]

List of drains and water ingress points (please copy and add/expand/explain):

1. Orange drains from aircon condenser tray, one each side of the transmission tunnel behind interior trim (which needs care and knowledge to get out undamaged)
- Full instructions on how to do this can be found at the following link: http://www.audipages.com/Tech_Articl...tordrains.html
- Ensure you have a large enough container to capture the water when you remove these, and prior to refitting, soak them in hot water to make them more pliable. They look like this:



2. Scuttle drains under windscreen scuttle panel. Easily blocked by leaves, difficult to get at. IMHO it's not really the big nipples that are the problem, but higher up in the tray.
- hidden under the HVAC unit and best accessed using something like a piece of copper brake pipe to get it angled correctly to wiggle around, and it exits both sides of the transmission. A combination of hot water and kitchen drain cleaners used to clean them, and then flushed again with clean hot water. Location and image as follows:




3. Sunroof drains
- Four in total, one at each corner of sunroof frame. Plastic tubing is very pliable so extreme care when cleaning these out. Front ones exit at the base of the A-pillar (you can see them when you open the door), and the rear ones exit behind the back wheel. Illustration of layout as follows:



4. Boot cable grommets, especially on right side. MJ has a solution.
- Link to specific thread about these - http://forum.a8parts.co.uk/showthread.php?t=15456



5. Seals around rear light cluster in boot lid
6. Rear numberplate (not sure about this one, but I've seen people seal there)
7. Small drains under bonnet, either side close to the wing panels.
- About two inches long and exit at the back of the wheel arch. Location and image as follows:




8. Botang's Hole - Even though it's not a 'genuine' drain, it has caused lots of issues so should also be addressed. The following link shows very detailed photos of its location: http://forum.a8parts.co.uk/showpost....2&postcount=16

[HPsauce]

A few points about the scuttle and aircon condenser (orange) drains:

The orange drains, in theory, only ever get totally clean water so shouldn't get debris. In practice the tray is open to cabin air so some dust/debris gets in. BUT if the scuttle drains overflow muck from there gets in somehow making it much worse. The tray holds several pints!

Cutting the tips off the orange drains "cross", so they're a mm or so open seems to help reduce blockages.
In an emergency the passenger side trim panel is much easier to get off so clear that drain first. The drivers side needs the knee panel removing first which is a recipe for broken fixings.

When refitting (I dip in boiling water!) the two smaller collars go either side of the transmission tunnel metalwork, push through with fingertips until it feels fully seated.
There is thick insulation inside the cabin that the larger collar seals against. The cross end obviously points down out of sight.

I find that ensuring the scuttle cover is precisely fitted to the base of the windscreen and cleared out regularly reduces the frequency of blockages.
If it doesn't fit snugly debris, leaves etc. just wash down the windscreen and straight into the drains.
You can peer into the tray (under the HVAC air intake unit, from nearside is easier) with a torch to check for water build-up.

I use a flexible plastic pipe and "suck and blow" down it to agitate the debris, after first syphoning off any deep water then adding hot water and detergent.
In my case the blockage seems to usually be in the tray, once that's softened by heat, detergent and agitation it "whooshes" out through the pipes.
I think once warm the exits there are large enough and far enough down that the flow just goes straight through. No need to trim them.
(Though they are almost totally inaccessible anyway unless the engine is out!)
Preventive maintenance of very hot water and detergent flushed through regularly I heartily recommend. I've got an indoor watering can with a very long spout that holds a couple of litres and does the job well.

[Markiii]

yey for this thread, I've been reading loads of threads on blocked drains and until know was none the wiser, keep it coming

[Green Goblin]

Originally Posted by steamship

7. Small drains under bonnet, either side close to the wing panels.
- About two inches long and exit at the back of the wheel arch. Location and image as follows:

Where exactly are these? I just can’t see them
Do I have to remove anything to see them?

I just wanna grab them and pull them out!!

Incidentally, i have the car back and supposedly the drains are all clear now.
But i wanna AT LEAST be able to see where those rubber teats above are because i sure as hell can’t find them...

[The_Laird]

They are high up in the wheel arch, towards the rear of the arch. If you put the car on full lock and get a decent torch, you’ll see them easily. Unless, of course, they’ve already been removed - but then you can see the hole. No need to remove anything.

[steamship]

Originally Posted by Green Goblin

Where exactly are these?

If you check the link I provided in post #11 above and search for the term 'Checking the Engine Compartment Drains', the next two photos show exactly where they.

EDIT: Better still, here's the photo:

[Audifan]

Originally Posted by steamship

List of drains and water ingress points (please copy and add/expand/explain):
3. Sunroof drains
- Four in total, one at each corner of sunroof frame. Plastic tubing is very pliable so extreme care when cleaning these out. Front ones exit at the base of the A-pillar (you can see them when you open the door), and the rear ones exit just in front of the back wheel. Illustration of layout as follows:

Who is the idiot that decided it is a good idea to have the front sunroof drains above the door hinge?! For a premium luxury car that was a STUPID idea!

Any tips on clearing out the rear sunroof drains if you don't have shop air to blow the lines clear?