I extended the sunroof drain hose outside the sills LIKE BMW SHOULD HAVE!
It's a bitch of a job to do on your own, but a second set of hands really helps.
The good news is that the area is accessible without needing to remove the front guards or door sills. Only the wheel-well splash guard needs to be removed - Pretty easy.
I was also happy to see there is no rust at the common points, but I gave the area a thorough clean and anti-rust coating for good measure.
Tips to help:
- There are 3 holes to pass through.
- Feed a coat hanger wire from the speaker hole at the top, down through 2 holes inside the body to the lower door sill.
- Use a 2nd coat hanger wire to fish the 1st out of the front hole.
- Feed the new tube down over the wire, using it as a guide.
- Fiddle around at the front hole to guide the tube out. This is where a 2nd person comes in handy.
- Join the tubes however you see fit (see below).
- FOLD the original tube back on itself when feeding the new tube down the hole. If you don't fold it straight, your whole tube length will be twisted and blocked.
I used gaffa tape. I tried using Heat Shrink on my first attempt, but it failed to hold together on the pull through.
I also considered a barbed reducer fitting, but there isn't much room to work with down there, and a reducer fitting is unfortunately not flexible enough to manipulate back into the hole.
I'll let the pictures speak for themselves.
Drain hose in action
https://imgur.com/AyCd0pT
Work log:
Remove the Splash guard inside the wheel-well
Pretty filthy!
Nice and clean, thankfully no rust.
Factory drain hose looking into the speaker hole
Factory drain hose looking DOWN through the speaker hole
Drain hose pulled out of the speaker hole
10mm vinyl hose. Best to feed DOWN from the top and fish it out of the lower hole.
Taped up with Gorilla tape
Trim to desired length.