The water is bing collected where the rear window regulator sits with the motor. Once the water fills up too high it will reach the window motor and destroy it. When I was repairing my window I did not adjust it tight enough so water ran off along the rear window into that space. It sounded as described by others. I believe that drain plug should be open all the time slightly so any water disappears instantly. From inside that space it looks like a very long drain plug that you have to pull from the inside or push up (into the car) from underneath the car.
Hi. Thanks for uploading this video. Just had exactly the same issue. About 2 weeks ago I thought I could hear water sloshing around somewhere but thought maybe it was just low level petrol in the tank. Then 2 days ago I had to stop quick and some water dribbled out from behind the rubber seal at the point the rear window meets the door jam. Then I knew I had problems. The drain plug you described on my E93 was actually under a small piece of trim which had what looked look a very small rain deflector attached under the car. Once that and the plug was taken off about 1 gallon approx of water gushed out. I've unblocked the drain plug and all seems well so far. Thanks again.
No worries mate. Sounded like my car had an extra fuel tank. That's exactly how I would describe it. Yes there is a Mud guard you have to remove to access the drain plug. But mine on the side you see in the video had it missing. Forgot to mention that.Sorry.
This had been coming out at the rate you see for at least 30 seconds. There was that much water in there I had to get my phone from inside the house then I started filming...
Raise the roof, the gasket up at the bottom of the body, spray underneath WD40, gasket back. Plug out the bottom of the floor and drain the water, close again and watch. I solved the problem.
Hi Tucker. Good question. It was coming from between the inner wing and outter wing. No water in or near the battery. It's the draining area for the roof. The bung which was removed is a drainer and it's supposed to drain as the water enters . The bung has 4 segments which is supposed to allow the water out. But they were blocked. So I had to remove the bung with pliers. It's a twist lock fit. I estimated 30 litres of water was in there. I could hear it sloshing around.. Thanks for the comment.
@@JonBoy1970 i have the exact issue in my Z4 but do i need drainage when this water sloashing sound dissapeared? Sound of sloashing water dissapeared after taking a ride
