Leak causing water in the boot

[Azio]

Hi,

I seem to have a leak somewhere causing water to go into my boot. I noticed the board covering the battery in my boot was slightly wet. After removing the board there was a small amount of water next to the battery compartment and the surrounding carpet was wet. I have checked the inside of the boot lid and all is dry so no water is coming through there.

I believe the source of the leak is coming through where the red and black wire is leading to as the carpet around there is where it is the most wet. I have no idea where these wires lead to and find it strange that the water could be coming up through the hole? Apologies for the dark pictures. I will try to get some better ones ASAP in the daytime. Any help is greatly appreciated.

Many thanks

 

[dhobbs]

Is the water coming from the sound insulation?
Might be the seals around the lights.
Also some cars had the air vents (behind the bumper) installed incorrectly.
Is there any evidence of water coming from the rear wings where they screw through into the boot?

 

[Azio]

Hi Dhobbs,

Thanks for replying. Where would I find the sound insulation? I have checked the seals around the lights and the inside of the rear windscreen as it's a coupe 'should have mentioned this in the post'. I cannot see any clear indication where it is coming from. I will try and take a video tomorrow as it's probably easier to show the issue. It definitely seems to be landing in a strange spot... I should probably strip the carpet out to get a proper look, hopefully it isn't too hard. I will post a video tomorrow to give you a better image. Thanks for your help.

 

[Ewazix]

Whatever it is you will need to pull out some of the trim to get to the source. The boot air vent flap (that allow fresh air to flow from passenger area heat & vent to the outside) located in the boot might be the problem and they would affect the area around those cables by the look of it. Worth a read, it looks like a nice little lock-down project so let us know how it goes

Previous topic https://z4-forum.com/forum/viewtopic.php?f=3&t=61611&start=15

Real OEM https://www.realoem.com/bmw/enUS/showparts?id=DU52-EUR-09-2007-E86-BMW-Z4_30si&diagId=64_1272

Part for sale (lots of shonky knock-offs also available!) https://www.pantritrading.com/bmw-e85-e86-e89-boot-trunk-air-breather-vent-flap-64226909340.html?___store=default&gclid=Cj0KCQiA9P__BRC0ARIsAEZ6irh-WvHNYBLsDmvMW3bY8cinpF2yUhuBLPkMVpq-RgK6hg2VbTEV2NYaAqP3EALw_wcB

 

[dhobbs]

to get to the sound insulation just remove the rear light cover in the boot and then pull the carpet back. The sound insulation in the wings can act as a sponge and soak up lots of water hence masking where the leak is coming from.

 

[HU51A_FU]

Maybe also do some background checks if you can in terms of whether it ever had any repairs around that area, not uncommon for panels to be repaired or replaced causing alignment issues/bonding/seals to be mis-fitted or never replaced when parts have been replaced.

Worth a stripping out in the boot and get in there and have someone hose down the car for a good 15 mins to see where the water goes.

 

[firebobby]

Is your car parked on the level ?

 

[Ewazix]

opcorn:

 

[davidmudley12]

I saw a YouTube video recently that suggested the blocked roof drains can cause water accumulation in the battery well. I’ll see if I can find it again to see if it can help shed any light on your issue.

 

[firebobby]

If I park my car facing up hill, I get a wet boot. The other way round or on the level and it stays dry

 

[dhobbs]

If I park my car facing up hill, I get a wet boot. The other way round or on the level and it stays dry

I found this out years ago so never parked that way again. Do you know what causes this?
Is it the dreaded drains overflowing or the seal around the lights?

 

[firebobby]

If I park my car facing up hill, I get a wet boot. The other way round or on the level and it stays dry

I found this out years ago so never parked that way again. Do you know what causes this?
Is it the dreaded drains overflowing or the seal around the lights?

I'm not sure, I just know not to park it nose up :wink:

 

[ph001]

Drains on a coupe? My money is on the boot vents.

 

[Azio]

Sorry for the delayed response, I have been super busy working over lockdown. Also thanks for all of your help/suggestions already. I really appreciate it.

I stripped some of the trim out namely the back plastic panel and 2 panels for the rear lights. Behind all of that is bone dry. Unfortunately, I don't quite know how to take out the side carpet panel to fully access the wet spot. I have uploaded a video to youtube to better describe the problem. Once again thanks for your help. I must also admit am very much so a novice with anything to do with working on cars/removing trim etc so apologies in advance for any dumb questions.

Also just to clarify, I am always parked with my car facing down a small decline.

Youtube Vid - https://youtu.be/MHf5tjIfWMU

 

[Azio]

Added pictures of the removed trim in case you cannot access the video.