Condensation Issue

[CharlieD]

Hi guys, been lurking here for a few months now... am now a proud RS4 owner of 2 months

Had some minor issues... I get a lot of internal mist buildup generally... today I ran the engine whilst running the vents at "windscreen clearing mode" for a few minutes (so I could actually see!), drove down to the local garage to buy some stuff, and noticed this as I was putting the shopping bag in:



Pretty sure that's not normal right? Is this enough info to make a sound diagnosis of the problem?

Really hoping there's an easy remedy for this...

[PetrolDave]

That's not condensation, that's water running out of the heater plenum - which likely means that the plenum drain hose is blocked.

It's usually buildup of rotted leaves etc. which is easily cleared, once you get to the drain, with a screwdriver or similar.

[ChrisW]

Im getting a lot of interior moisture too, not quite on the scale of the above but it is there nonetheless. I used to have to do this on all my old Golfs, where is the plenum hose located on these? I'm currently in bed with man flu, so i'd be grateful if someone could tell me so i can go out armed and ready.

[R1RS4]

Im getting a lot of interior moisture too, not quite on the scale of the above but it is there nonetheless. I used to have to do this on all my old Golfs, where is the plenum hose located on these? I'm currently in bed with man flu, so i'd be grateful if someone could tell me so i can go out armed and ready.

Sorry mate if you have man flu, you cannot go anywhere, you must stay in bed. Man flu is so serious, it's the equivelent of a women giving birth, plenty of top gear, street outlaws, gold Rush, counting cars etc

The car comes next, good luck hope you pull through

[geordie jay]

I would like to know where the plenum hose is aswell? there a right f£$%k off tree in me garden and so annoying this time of year when leaves are falling off

[davers6]

Try and park facing downhill can get in then

[Ian_C]

My B6 never had an issue, but my B5 is bad for condensation in this kind of weather.

[CharlieD]

That's not condensation, that's water running out of the heater plenum - which likely means that the plenum drain hose is blocked.

It's usually buildup of rotted leaves etc. which is easily cleared, once you get to the drain, with a screwdriver or similar.

Thanks PetrolDave, I took out the plenum cover and had a look-see, sure enough there was about an inch of water sitting there at the bottom on the N/S. Wasn't able to see much of the O/S but in any case I managed to clear the blockage using a steel drain unblocker tool.

What still worries me a bit though is:

• How the hell the water gets into the cabin in the first place!
• Getting at the other drain seems impossible as the brake servo is in the way.

As I was reading about this on the web I happened to come across a post about my chassis being one of the models affected by a specific Audi recall regarding the plenum drain grommets... will give the dealers a ring tomorrow about it.

[PetrolDave]

How the hell the water gets into the cabin in the first place!

The same way the air gets into the cabin - through the footwell vents. If air can get through (which it has to for the heater to work,) then (rain) water can get through. The drains are at the lowest point in the plenum chamber so when they're unblocked the (rain) water exits that way, but when the drains are blocked the (rain) water has to exit through the footwell vents.