Water in boot under spare wheel

[mhurer]

I have a 2014 TFSI saloon and when I looked at the boot around the spare wheel the other day and around the battery I noticed a small amount of water, with lots of what looked like condensation as well around the battery and spare wheel. I cleaned it all up but today, 3 days later, a small amount of water is back.

Any ideas where this water is coming from and how it should be drained? Are there drainage holes somewhere that might be blocked in the boot, or is this condensation just normal this time of year? Water is clean.

[john81]

Hi. Do you have a sunroof?

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[mhurer]

No sunroof. Also can't see water anywhere else in the car - carpets all clean etc.

[Shaka1976]

Rear light seals

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[mhurer]

Rear light seals

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Thanks. I'll have a look at the weekend but from what i've found googling/searching this seems to be a common problem with the early B8s - mines a facelift B8 less than 5 years old.

[Roonster]

There are vents designed to allow the pressure to escape when you slam one of the doors. They are hidden by the rear bumper below the lights. In normal driving conditions they are meant to be closed. They have a tendency to stick open allowing water (spray)to enter. It's a bumper off to replace them. Have a look behind the side panels in the boot and you will spot them.

[mhurer]

OMG I think you have got it spot on. I think the problem started a couple of weeks ago after a shunt into the side of the bumper, so what you say makes sense. I'm getting the bumper removed next week at the bodyshop so i'll get them to look at the damage / vents at the same time. Do you have any part numbers?

Thanks

[Roonster]

Sorry, i don't have the part numbers. One of mine is working fine so I taped up the duff one from the inside until the better weather

[VAG-Abound]

Is is it one of these? Audi A4 B8 RS4 Single rear Vent behind bumper 8K0819161C New Genuine Audi part | Deutsche Parts (https://www.deutsche-parts.co.uk/index.php/audi-a4-b8-rs4-single-rear-vent-behind-bumper-8k0819161c-new-genuine-audi-part.html)

[mhurer]

Looks very likely - i'll ask the repair shop to have a look when they repair the bumper. Thanks.

[mhurer]

Well the body shop had a quick look and hose down and couldn't find the source of the leak. They said the next stage would be to strip the boot of the linings (at a future date) and try again.

So I did the same at home - dried the boot completely and hosed down the hole car for a good 10 minutes but couldn't find any leaks. I then went for a drive, up and down hill, with sharp left and right turns, and still nothing. The vents behind the boot looked clean and dry.

This morning I checked the car after rain last night and there is a small amount of water again collected on the bottom OSR in the spare wheel well. The top of the boot lining was also a bit wet (see diagram), so I assumed it was dripping from the brake light area of the boot lid but that all seems dry as well, then I assume it is dripping into the spare wheel area from there. The (OSR) side of the boot lining seems to be dry.

So seems to be rain water not road spray, so I guess the next step is to strip the lining of the boot lid to see if that is wet. So I guess it could be the brake light seals as previously suggested, even though that area seems dry. Lights are sealed LED units.

Any thoughts?


Edit: Having said that, I do remember there was a small of amount of water near the vent when I previously cleaned the boot, so I guess it could be trickling down from there and not immediately visible. Boot rubber seal itself looks fine and i've treated it to keep it subtle. I guess I could try replacing the vent or taping it off, and sort out the OSR brake light seal and see if that solves the problem.

36462

[mhurer]

Quick update. No water since taping off the air vent on the OSR, so I guess that is most likely to have been the source of the problem. When I get time i'll get the bumper off and replace it.