JonathanC81

Hi all,

I'm having problems with my orange A/C drain cowl pipe and after exhausting all resources on the internet I hope someone could advice here.

My car is a UK model 2001 Audi A8. AKC engine code and 4D2 Chassis code.

I noticed water sloshing around the dash and water pouring out the sides of the footwell area so I removed all the trims and try to unblock the orange pipes as adviced by many websites.

I find that more water is pouring out from the left side compared to the right side. I don't have compressed air so I used a flexible tubing to try and clear as much as I can. The tube goes in a considerable length. However on the right side (my driver's side) the tube won't go in past 5 inches. Something is stuck at the "neck" area of the orange pipe.

The really strange thing is that I find water is always pouring out more on the left side compared to the right side despite this problem...

Anyway, I am just wondering if I could just fully block off the right side? Is it a single tank with two drains or two separate tanks with individual drains?

silverd2

As I understand it, the drain hoses are at each end of one common tray under the evaporator. I used this method, which I assume you're trying:

http://www.audipages.com/Tech_Articl...tordrains.html

It worked easily for me.
BUT the Bentley manual, without a detailed explanation, says each hose can be removed by pulling it up out of the central tunnel. The large orange grommet (plugs into side of console) is an integral part of the hose.
If you try this, I'd like to see a report...theoretically the hose simple feeds back into place, then grommet plugs into hole with it's double lip.
WARNING : I've never tried this, but could be an easy fix...taking the hose out to clean it.

StanA8L

I have the same water problem after 6 inches of heavy rain. I would like to know if there is a better or easier way to unplug the cowl drain under the blower motor housing? (Without having an air compressor. I think I have cleared the orange drain tubes as shown with a hand air pump, but still had water in the ducts. I had water sloshing in the rear air duct in the center console. I snaked a tube in there and siphoned out 20 ounces of water. I also had more water coming out of the left side on my feet than right. It appears the cowl drain remains plugged?

Where would I snake a tube to siphon out remaining water from the front ducts?

Suggestions please?

JonathanC81

I am also intrigued by this. Is it possible to provide a pdf copy of the manual so I know what I am doing? The right orange tube is completely blocked as I can't run my flexi pipe down there.

I am currently using a combination of tyre compressor and also a flexi plastic tube normally used to guide wires through wall cavities.

JonathanC81

This is interesting. For me the (very cold) water drains out the black piping after disconnecting the orange one. I too hear sloshing sound and water will drip out when its really full.

I am not sure about the front ducts though, perhaps for you the water is getting through the front HVAC?

silverd2

First I think Jonathan was only talking about clearing the inside AC drains, but the outside drain in fresh air plenum has to be addressed too...and clogs more often.

There's a couple of factors involved, if the plenum drain is clogged the water can enter through the AC housing and if the inside AC tubes are clogged the system can drip on your feet AND fill the center air canal...both need to be cleared to mostly** solve the problem.

When AC drains are clogged, even without ANY rain, they will still drip AC water on your feet up front.

To clean the plenum drain, I did used compressed air (or a leaf blower), but NOT quite the way the AudiPages article described. I just used it to blow out all loose material from the plenum from both sides of fresh air blower. Then from under the car (jacked up), you can just see the ends of the drains on both sides up between the fender wells and engine. I used a straight piece of PVC water supply pipe (kitchen/bathroom sink type) to feed up into the drain outlets, to break loose the built-up debris, while alternately pouring lots of hot water into the plenum drain to flush em out. Worked like a charm. I periodically (fairly often), blow out the plenum with the leaf blower (with top covers removed) and pour a large pan of hot water, just to check em and keep em clear.

**The unfortunate thing is, even with everything clear, most 2001 models and before can still get water in the center air canal after a heavy rain...mine still gets a little after torrential downpours. Late in 2001 or after, the seal between the fresh air blower housing and the inside of the cabin was changed from a foam seal (bad idea) to a solid rubber seal (good idea). Eventually the foam seal degrades to to point of letting water into the inner AC housing during heavy rain or clogged drain high water....so it doesn't have to be deep enough to overflow the fan intake.
Took me a while to figure this out, after learning of the seal change and actually observing the water level in the plenum during heavy rains...enough to still get water into the tunnel. Getting to this seal, to change it out is about as involved as a transmission swap, so didn't try it.
I live at the top of and my tunnel empties itself going down the hill and/or some hard braking...not sure how it drains, but does NOT come out in the cabin...I've checked everywhere...not on or under carpet...maybe getting out the AC drains somehow (seems impossible, but it works). Maybe another duct drain up front that doesn't show in drawings(?)...don't know, don't care...just know it works every time for me.

Warning, hitting brakes hard immediately after a hard rain can overflow the sunroof drain into the front headliner...esp if rear sunroof drains (accessible in the trunk/boot) are clogged. Once I cleared those, this headliner leak under heavy braking went away.

I love my A8, but they are plagued with water drainage problems. Most can be cured, if you keep after em.

silverd2

The Bentley CD rom has built in protection that won't let me download copies (no way I've found...copyright protection)...only a paper copy for myself. BUT it really doesn't show or explain anymore than you've seen yourself. The orange hoses in the cabin ARE the ones that are supposed to pull up and out, with the grommet attached.

The outside plenum (besides the hidden large center drain)also has 2 side drains into the fenderwells...those clear by pinching end tubes in fender wells.

silverd2

The Audipages article is much more comprehensive with better photos than the Bentley....Bentley merely states that the tube is removable by prying orange grommet (integral with orange tube) from the console and pull up and out. No one shows what the entire tube looks like.
Had I experienced a clogged tube I couldn't clear, I would have tried removing the tube myself, but wasn't neccessary. I would feel better about doing this than possible puncturing the tube trying to hard.

JonathanC81

Hit the nail on the head there pal. I love my A8 and I can't believe it is plagued by such a simple problem. Believe it or not I never had this problem with my last car which was Japanese...

I think my problem is only from the A/C compressor tank. It doesn't rain too heavily here just light drizzles and I don't notice any water gathering in the rear bulkhead of the engine compartment. I am tempted to pour some water just to check but also paranoid that I will make things worse!

I am not even sure exactly where to pour the hot water at...

I will have a good think if I will try to pull the right side orange pipe out. I had a play and I am not sure if it will fit back after I pull it out...

Saying that, is there anywhere I can get a "blueprint" or some kind of diagram showing the A/C pipings for the 4D2 Audi A8?

StanA8L

Thanks for the replies Jonathan and silverd2. I know there are places I could find this out or purchase manuals, but I haven't so I'll continue to ask the dumb questions.

I believe the A/C drains (oranage tubes) are not plugged. The tubes in the fender well were plugged, but not sure they would actually place water into the plenum? Water would probably just overflow into the engine bay?

So, I agree my plenum drains must be the culprit. In fact, with the covers removed I can see standing water. My problem is I can't reach it. I don't know where the drains are actually located. The "audipage" showed the approximate area, but is that because they are under the entire blower assembly?

Are the plenum drains accessible from underneath? Do they look like the rubber ones in the fender well? And will then get plugged with road grime the same way?

I too think the seal has to be adding to the problem. Are you saying the new rubber seal design is not suited for the 2001, or just don't try it myself?

Thanks for all your help!