G21 very wet under the boot floor

[mikey_p]

Hi all,

I picked up a 2020 320d G21 on Saturday and mostly very happy with it.

However on Sunday afternoon I noticed in the compartment that stores the parcel shelf there was what seemed like a bit of condensation. Lifting up the larger compartment (towards the back) I found the inside of it to be really quite wet and then when I removed the parcel shelf and the flooring it sits on, I found the sound proofing on the underside completely soaked (dripping wet). This area is the large area circled in red, nearest the boot hatch. There was also a small amount of water lower down in the battery area (small pools that needed a bit of kitchen roll to remove).

What I didn't understand is there was no water anywhere else, the boot seemed completely dry, and I don't understand how that area has got wet. I had 3 thoughts:

1. Aggressive pressure washing by the garage (although I'd expect the main boot area to be a bit wetter?)
2. Rear washer jets as I'd been figuring out how to work them and had sprayed them an unusual amount. However I repeated this after drying and it didn't get wet again.
3. Driving through very large puddles, as it was pretty flooded yesterday, with the water coming up from the floor?

I repeated number 3 today (purposefully drove through some large puddles) and there was a very small amount of water in the battery compartment (can just be seen in the pic) and the sound proofing above the hole I've encircled was a tiny bit wet. This doesn't seem right, but also doesn't seem like it would cause the major damp issue under the parcel shelf storage, as that's about 25cm higher then the battery compartment.

It's booked in next week to be looked at, but I'd like to do a bit of troubleshooting as it'll be hard for a garage to replicate. Any suggestions what the cause could be or how I can narrow the issue down?

Sorry for the lengthy post, any help appreciated 🙂

[bigdom]

Block drains would be the likely culprit. Does it have the panoramic roof?

[mikey_p]

Nope, no panoramic roof. I had noticed they are often the culprit, but not in this case.

I'll do a bit of Googling into unblocking the drains and figure out whether it's a job I think I'm capable of .

Thanks

[d_a_n1979]

FWIW I had this issue on my previous F01 730D

Turned out the boot seal hadn't been knocked back down hard enough after the rear bumper had been replaced by my bodyshop pal and it was letting water in after washing etc...

Only noticed when I went in to replace the battery and found an inch of water in the corners etc...!

Removed the seal; made sure it wasn't damaged and knocked it back home hard with a rubber mallet; zero issues after that

It could also be rear light cluster seals (maybe) if they've perished or been nipped when the lights have been fitted etc?

[mikey_p]

d_a_n1979 said:

FWIW I had this issue on my previous F01 730D

Turned out the boot seal hadn't been knocked back down hard enough after the rear bumper had been replaced by my bodyshop pal and it was letting water in after washing etc...

Only noticed when I went in to replace the battery and found an inch of water in the corners etc...!

Removed the seal; made sure it wasn't damaged and knocked it back home hard with a rubber mallet; zero issues after that

It could also be rear light cluster seals (maybe) if they've perished or been nipped when the lights have been fitted etc?

It could be something similar actually. Whilst investigating thr issue I found it's actually got a Witter removable towbar which was a surprise (a nice one, as I was thinking of getting one fitted). But I guess in fitting it the bumpers have been removed and various things in that area tampered with 🤔