Johnyoungiii

Hey guys,

I have been having a problem with my 2004 530i, after heavy rain water seems to accumulate on the back passenger floor, I've checked the trim and cannot find an entry point. Has anyone else had this problem? What could be possible solutions to the moister build up?

Thank you for your time!

John

tonyb635

A good starting point are your sunroof drains. The the two in the front are visible and easy to check. The two in the rear are not easy to get to. My guess is that they could be blocked or the drain tube cracked etc. Next I would replace the seal around the sunroof if you haven't done so already. This is the seal that is on the roof body when you slide your glass back. There are plenty of DIY out there to help guide you on this. Even if your seal looks good, it doesn't mean that it is. Most seals get hard and don't work so well after 3-5 years. If you car is outside a lot it could be quicker. A new seal is really soft and also makes for a quieter cabin.

KyleB

+1, check and clean sunroof drains.

Johnyoungiii

Thank you for the response,

I have checked all of the seals and drains and they seem to look like they are in great condition. Later this week I am going to pour some water with dye over each of the seals, wait to see if the water on the floor board starts to change color, at least then I can isolate the area. The moisture issue has gotten worse over the last few days. 3/4" builds up, I'll vacuum and even if it isn't raining, or lightly sprinkling, water builds back up to about 3/4". Could it be built up somewhere and just pouring out when the present water gets vacuumed out?

tonyb635

Have you checked the front floor area too? That seems like a lot of water and like you are also thinking maybe it coming from somewhere else. I've seen the front pass floor area get wet from various things. A good test for you main sunroof seal is too drive on highway and slide back together inner manual slide and then close it. If you hear more noise with it open where only the heads is exposed you probably should look at changing the main seal. When the seal is in good sago there really isn't any notable sound change when opened or closed

Cricketts

Also, check the bottom of your trunk for water. If a lot of water, expect a $1500.00?? bill. Also check the rear roof liner for water stains which would indicate plugged rear drains.

Good luck.

Johnyoungiii

I have checked the front floor area and its dry. The only source of moisture is the spot where the water is built up. The only reason the front has gotten wet is when I'm driving to vacuum out the water and the water sloshes forward from braking. But the trim around the floor is dry, trunk is dry, and headliner is dry. I am going to do further testing of the vapor barrier and drains tomorrow. Where is the exit point of the vapor barrier? By the wheel well of the respective side?

tonyb635

The sunroff casset drains just behind the front wheels and the rear I can't remember if it's in front of the rear tire or just behind it. I believe you can see the drain tubes when you look underneath. Thats very bizzar that the water is only in the area and there is no trace to a possible source. I would imagine that if its in the floor there would be other areas as well that are wet since it has t get to the floor area.

pcy

Is the water coming only after rain? Water could be coming from the door (bottom).

To test this theory, pour water on/above the door and see if the water trickles in.

houbmw

could have to do with a faulty vaporshield in the actual door.