The most Lemon Audi A6 Avant strikes again

**ragebe** · 12-11-2014,07:15 PM

BUMP. Was having the car valet cleaned today, wet carpet, near side footwell. Had a look under bonnet, plenum chambers full of water again (and oak leaves)

**gupsterg** · 13-11-2014,12:11 PM

First clear plenum chamber, if water level get high enough then air intake for AC/fan blower can be inroad for water.

Easy check is if pollen filter wet, located in interior, there's a how to on pollen filter change on the forum if you don't know location or done it before.

If your passenger side section is getting wet and you have no rear washer pipework faults you maybe having same fault as me.

So far I can recall 5+ peeps having same issue as me

, I'd feel so gutted to know there's another now!

**chilledgibbo** · 13-11-2014,09:04 PM

Gupsterg

A big thanks to you for starting this thread and persevering with updates. The same thing has happened to my 2.7TDi Avant which I have only owned for 3 months. I discovered a wet patch in the back passenger side foot well two weeks ago after a very rainy trip to Glasgow. My indy mechanic had been sourcing the leak. One issue was a warped ECU box which was not sealing properly. However after that was replaced and sealed, along with the pollen filter housing water was still coming in, and I noticed eventually that it was coming in through one of the grommets in the floor above the chassis rail, exaclty as you decribed in the thread.

The cause is the plenum drain letting water drain on the wrong side of the heat shield which then enters a small round hole direct into the chassis rail, and when it gets full it's forced through the grommet in the floor. The plenum drain has now been modified with a pipe to carry water to the other side of the heat shield, grommets have been removed beneath the chassis and the grommets in the floor have been sealed.

I think what we have here is a design fault with the plenum drain not being long enough to direct water to the right side of the heat shield. I hope now that in my case, as well as yours that there should be no more water getting into the cabin. I'm getting a bit fed up now with a car that has no carpet! All I have to do now is wait for it to dry out properly.

Cheers fella, this has really helped get to the route of my problem.

**gupsterg** · 13-11-2014,11:19 PM

OMG! I'm shocked at how many more cars with same fault are coming forward, sorry to read your going through same thing.

I just wonder how many unreported cases there are?

.
Thank you for reading thread

and an even more big thank you for sharing info on entry point

.

I can report that I've not had repeat of water ingress

, I did seal grommets on drivers side as well as passenger side as really did't fancy 4th time of interior removal as would have been more

.

**garfayliu** · 13-11-2014,11:57 PM

Epic thread. Well done and big respect to Gup. Have owned my 2008 Avant for 2 months, will definitely check for this issue over the weekend. Fingers crossed. Hope all others can fix their issues.

**gupsterg** · 14-11-2014,08:31 AM

Welcome to the forum

, thank you for taking the time to read thread and commenting

.

I hope you don't have the issue but taking the steps to do preventative measure isn't a bad idea as it's such a PITA to remove carpet and dry it.

**chilledgibbo** · 14-11-2014,02:14 PM

Just out of interest, where did you get the 20p bungs from and do they make a watertight fit? I'd like to make sure all are sealed on both sides myself.

Thanks

**gupsterg** · 15-11-2014,09:36 AM

IIRC I got them from a DIY store, the bung is just a Link:- blind (closed) grommet

Rereading Link:- post 127 the hole in floor is 30mm and grommet was 32mm plus my comment of lubing it for insertion (

) means it must have been tight. Therefore watertight but for good measure I used duct tape over the top, IIRC it's Unibond duct tape.

As it has been 2yrs now since doing this fix I may just one day lift carpet to check if all well. I do feel very confident all is fine as the past 2 days there has been heavy rain and all sections of carpet feel dry, no condensation on back of rubber mats and have observed water drain out from bottom of car

.

**chilledgibbo** · 15-11-2014,01:04 PM

Originally Posted by gupsterg

IIRC I got them from a DIY store, the bung is just a Link:- blind (closed) grommet

Rereading Link:- post 127 the hole in floor is 30mm and grommet was 32mm plus my comment of lubing it for insertion (

) means it must have been tight. Therefore watertight but for good measure I used duct tape over the top, IIRC it's Unibond duct tape.

As it has been 2yrs now since doing this fix I may just one day lift carpet to check if all well. I do feel very confident all is fine as the past 2 days there has been heavy rain and all sections of carpet feel dry, no condensation on back of rubber mats and have observed water drain out from bottom of car

.

Thank you. I gather I'll need at least four- two for each side. At risk of asking a stupid question what lube did you use? I'm thinking WD40 or similar or am I way off? I'm going to order some grommets today, as I plan to try and put the carpet back next week. The existing dry grommets were sealed in with RTV sealant to make them watertight but I think I'm going to replace them with a 32mm blind grommet for a guaranteed tight seal.

The carpet by the way was a PITA to remove, especially under the driver pedals area and foot rest (mine's a manual). I ended up slightly tearing the carpet by an inch from the 'V' shape behind the kick panel, but this won't be visible and I'll used duct tape behind to stop it from going any further. I'm really not looking forward to trying to put the carpet back in when it comes to putting it round the footrest and back under the pedals. I'm looking forward though to having a nice dry carpet in the car, hopefully next weekend if it is dry, as I have a couple roadtrips to make around Christmas.

**ragebe** · 16-11-2014,01:48 PM

Originally Posted by chilledgibbo

Thank you. I gather I'll need at least four- two for each side. At risk of asking a stupid question what lube did you use? I'm thinking WD40 or similar or am I way off? <snip>.

WD40 isn't a great lubricant, it's main purpose is as water-dispersal and was the 40th such formulae to be tried. Water - in it's purest state - is the best cleaner/lubricant known to man (unless science has moved on in the decades since I studied this stuff) You're probably better off with a silicone-spray lube.

Yesterday, my plenum chamber was filled halfway up and I spent about 5' draining the water by popping the bungs. I have so many leaves and bits of leaf in the plenum chambers, that I would need to remove pretty much everything located to clean it all out. I'm going to try a garden-hose with a spray-gun to see if a jet will push all the leaf parts out. I suspect this is going to be an ongoing problem, until such time as I remove the motorbikes, bicycles, golf-clubs and kayak from my side of the garage and put the car in there instead. I am toying with the idea of a car cover as I think this will stop water ingress, whilst the car is on the drive.