I got a wet trunk.

[Jand3rson]

Aight R3V, now that I've not only decided to live in one of the 10 rainiest cities in the country, I'm also currently having to use the E30 as my daily. Which means I've now experienced something I never had issue with before, I got a wet trunk.

There's no standing water, but it's damp in there. Right now, there's a layer of condensation on the whole underside of my trunklid. The carpet is damp to the touch, and anything in there gets damp. It also kinda stinks.

So what do I start checking? First thing is since I don't have an antenna anymore, I have a rubber plug in the hole, and some sticky black mastic/putty type stuff jammed around it on the underside, but it's been years since I put that in. So beyond checking that, what's next to start investigating?

[dirtbag30]

hows the weather strip on the trunk itself that seals when the trunk lid is closed?

also the vents on each side of the car, under the bumpers.

i don't know how to explain nor do i even know what they are for. but are they letting moisture in?

[ak-]

Tail light gaskets. Sometimes they even look okay, but if they aren't plush, they don't really seal pressed.

[dirtbag30]

Tail light gaskets. Sometimes they even look okay, but if they aren't plush, they don't really seal pressed.

or this
didn't even think of that

[ELVA164]

The list, which I believe is complete:

-Antenna seal (replace it either way, it's cheap and worthwhile) (I know you don't need this step, but for completeness' sake it's here)
-Trunk gasket (even if it's soft, it may have lost its shape and won't completely seal.)
-Taillight gaskets
-Sunroof drain seals on each side under the rear bumper (these have to be special-ordered if I remember correctly, so plan to wait a couple weeks)
-Make sure the tube for the sunroof drain is completely seated into the side panel itself; over time the hose can dry up and pop out, dumping the water into the area inside the bumper
-Rear window seal

[Jand3rson]

Awesome, thanks for all the pointers, fellas. Maybe it will dry out enough this weekend to check it out.

[jeffnhiscars]

My 84 318i just started getting condensation in the trunk even when I haven't driven it. This thread makes me wonder if the body shop left the sunroof drain hoses disconnected :/

[M-technik-3]

Are your License plate holes all 4 closed? Have you cleaned your sunroof drain tubes? and along with that how old is your sunroof seal?

[rcsoundn1]

The vents are to even cabin pressure when you close the doors, but likely let moisture in as well.

[Navarone]

I got a wet trunk.

I just did the tail light seals and it fixed the leak there but the trunk is still swampy like you said. Even after letting it dry out. Before the new seals it was puddles and tail lights full of water and now it's just damp carpets and trunk lid condensation. Make sure you pull the read seat bottom, the trunk can drain to the cabin if the car is parked facing down hill. Noticed a little green mildew behind the carpet, gonna pull it all out and use some diluted bleach to stop the mold. Man I hate this.

[M-technik-3]

Take a ride to you local hardware shop and purchase some Damp Rid It works wonders the sell bags of the material to refill it as well.

[Jand3rson]

Are your License plate holes all 4 closed? Have you cleaned your sunroof drain tubes? and along with that how old is your sunroof seal?

License plate holes are good, I've never cleaned the sunroof drains or replaced the seal, though.

[M-technik-3]

You might give them a check but I would check to see if your trunk seal has any tears or appears flattened out as well.

[ELVA164]

All you have to do with the sunroof drains is test them. Pour water down each hole, then make sure a clear, steady stream comes out of the drains. Front drains are just behind the front wheels, rear drains are just behind the rear wheels. The "seal" is really only meant to keep water in the tracks, not out of the car altogether. As long as no water is making its way to the headliner, the seal is okay.

[Navarone]

I got a wet trunk.

I saw drain tubes behind the front speaker, they were loose and didn't seem to plug into something like the rear ones in the trunk do. Are they just draining into the car or something? I haven't noticed any moisture in the front of the car.