Water is leaking into the boot of my A3 Cabriolet and I have no idea where from - PLEASE HELP

Hi guys

So I brought an A3 cabriolet S Line beginning of August, haven’t had many problems with it, until the weather changed… I normally keep all my footwear in my boot all in their shoe boxes, after a long weekend of rain, Monday morning came and I needed the extra boot space so I moved all the shoe boxes into my house. To my surprise all the shoe boxes at the bottom were destroyed, completely soggy and flimsy and not in use, luckily the trainers are ok however the car is not. It is leaking from somewhere and I have no idea where.

This did happen some time ago and I just kept some of the shoe boxes inside my house and waited for a heavy raining day so I can work out where the leak is coming from. All the times it rained the floor of the boot was damp but wasn’t evident as to where it came from.

Until yesterday, when it snowed, the floor was soaked, see pictures below. The bottom left and right corner seems to be where its coming from, left side being wetter and even possibly the top right corner where the back seats are.

I did run my hand around the walls of the boot to see if they were wet, they weren't. however, the bottom left corner, up at the top (see the last picture for reference) was wet and it could possibly be coming from here.


Attachment 32385Attachment 32386Attachment 32387this last picture is a bit hard to work out but it is the top left-hand side of the boot opening, it's not visible in this picture but it did appear to be wet here.Attachment 32388
I have seen online it could be the backlight fitting not secure, just from looking them seem fine. If any of you could give advice on how to check this that would be great.

I have limited mechanical knowledge but regardless I have no idea where or how the water is getting, any advice would be greatly appreciated.

Get a torch and climb inside the boot. Have an assistant close the boot. They can spray a hose over the back of the vehicle while you shine a light into where it's coming into the boot. Could be rear light clusters. If you have vents in the body behind the bumper this is also a likely suspect area.

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ill have to give that a go, wont be until tomorrow evening but ill let you know the results. Hopefully it isnt a slow leak

Right ok, so after being trapped in the boot only equipped with the torch on my phone and my girlfriend using the hose to water all angles of the car, I couldn'tfind the source of the leak. However, after taking the small side interior panel off, the bottom of that little area was soaked (see picture at bottom for reference). And when compared to the right-hand side section which was dry. When I was in the boot i was looking in this section and I couldn't see any water coming from anywhere, does anyone have any ideas?Attachment 32399

Well from the photo it's coming through the air vent the black thing at the back of the photo. The seal around these vents are rubbish. Probably will have to remove bumper. Remove vents and take old seal of. You can either use new seals or what I use is Tiger seal. I use it on all water leaks into vehicles. It's a silicone type sealant. You will also need a silicone gun to apply it.

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Attachment 32402is this the air vent youre refering too?

Nope. The very big black item at the back of the photo almost central in the photo . Has lines and grids on.

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thank you Flapperjack,

I will be able to do this all hopefully sometime next week, 2 questions before I do, firstly, as its going to be a long task for me would you have any idea how the water is getting in or what angle the water is coming in from just so i can climb into the boot again and confirm it is the air vent.
Second, would i apply the seal to the vent from the inside or outside?

I would get some paper towel. Dry it get back into the boot look at that vent get someone to hose the outside and confirm it's coming in there. Remove the bumper. Remove the vent throw the seal away. Apply the sealant around where the seal used to live. Fit the vent. Wait a few hours. Get back into the boot spray water. Confirm it's gone. Fit the bumper. Make a cup of tea and enjoy life again. [emoji6]

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Hi
I have a leek in the same area only occurs when it is raining either parked or on the move, so I got hold of a full service manual for the Audi which covered removing the panels so that I could do the work myself, got the trim removed in less than 30 minuets to expose the area but you cannot see any thing at all, it's all enclosed and the hood motor is also blocking the only access to the area as well tried a USB camera on a lead but no use too much around the area.
So I turned my attention to the wheel arch which others have reported, removed the wheel and took off the wheel arch liner which had 12 screws holding it on at the top of the wheel arch there is indeed a drain for the hood which runs out onto the wheel arch cover, all this area was covered in derby this drain had a flap valve in it which I assume is there to allow water out but not in this was all gummed up with sludge so this could be causing my problem, I also noticed that this drain was not sealed around the edges where it goes through the body work so could allow water to enter ? as it is rubber I am a bit wary about sealing it with silicone as it might with time effect the rubber, I am also going to look at the other side to see if a similar arrangement exists there, will keep you posted on my progress. The side vents usually let water in when the car is moving this is caused by spray hitting them, when the springs on them become week and they do not seal correctly and if you think that this is the problem then they need to be replaced.

Hope this helps