obiwan, thank you also. great post and find of that bimmerfest URL

mmitev, thanks for the follow-up post

now I better stop procrastinating and go check those rear drains. so help me out because I have ADD, I think we're concluding here:
1) the rear flapper valve is the apparent "cause" of this issue because it gets gunked up easily?
2) removing the flapper valve "permanently" allows the drain tubes to drain cleanly just like the front tubes?

 

1- I think so
2- yes but I think one needs to blow these out with compressed air. How? I don't know
I am planning to use the compressed air canister that I have for use on computer keyboards with a tubing attached

 

obiwan, thanks. let us know how the canned air solution works.

 

dose anyone have pics where they are located?

 

I had the same problem, caused by water leaking into the window electrocis when the rear water wipe burst

 

Someone here or in another topic promised to clean the drainage pipes and to do a DIY, but never came back...

So here we go:

1. This (in the yellow circle) is the nasty pipe. Yes, you have to remove the bumper to access it:


2. And this is the "valve". I have a hard time imagining what function this valve has, except getting fu**ng stuck with dirt. It looks like it is designed to prevent air getting into the car (as presumably water can hardly travel up to the sunroof level, assuming the car is not underwater..).
This valve was clogged with dirt and could hardly be opened by hand, let alone let water run through it:


3. First I speculated with the idea that cleaning the valve would solve the problem... then I decided I did not want to remove my bumper for this in the foreseeable future, so removing the valve alltogether sounded like a better idea. I did it, and - surprise - the pipe itself was clogged with dirt approximately 2 inches above the valve! :


4. And now this is the cleaned pipe, with nothing to stop water running through, and nothing alowing dirt to pile up :


I left it like this and did the same on the other side. I hope the problem is solved.

Now someone has to tell us where to find the front pipes and how to access the valves?

As far as I know these front pipes are getting clogged up since the E34 Touring..

 

Front ones are towards the front when you open the front door.
NO valves on the front ones!

 

mmitev, thanks for a great DIY post. what year is your car?

 

Its 2004.

At heavy rain I had water dropping in my trunk, from or along the drain tubes. water went into the two side compartments of the trunk, then into the battery compartment, and once after a whole night of showers it flooded the spare wheel well.

After driving it for a while (without knowing obviously) I got some error messages like "Electrical fault. Stop the car and search for a dealer.". Then the iDrive stopped working. The iDrive module was drowned and I had to replace it. I was lucky it was the only part that got screwed.

I hope this whole issue is fixed forever now. I don't think I have a leakage problem with the roof by itself.

 

mmitev, in post #20, you cut-n-pasted a DIY from a Bimmerfest article where the owner of a 2006 did not remove the bumper. did those instructions not work for a 2004 like yours?