excellent write up. I didn't even know this problem existed on the convertibles until seeing this post. I went outside and tested both drains with water. Passenger side was flowing very nicely, but driver's side was draining very slowly and holding some water. I tried flushing it down with some hot water but no go so I followed this DIY to lift off the left side of the convertible frame. Wasn't hard at all. Getting the frame off the base was a bit of a bear because you have to put pressure on the front of the top so it balances itself a bit. Sure enough, I got to the hole and it was plugged up. While I was in there, discovered the front-facing base nut was completely loose and about to fall off! I am assuming from a previous repair job by the dealer.
It's nice to be able to leave the hydraulics connected and just move the base out of the way. Took my pipe cleaner set from harbor freight and went to town on the drain. Flushed it a few times and it is now sucking the water down very quickly.. even making sucking sounds like the other side. Thank you!
GT1/ISIS/MoDiC = Factory authorized diagnostic system used by BMW dealerships across the world.
NCS Expert = BMW Factory R&D programming tool available on the internet (not intended for the public and not available to the dealership network)
OEM = Genuine BMW part only available from a franchised BMW dealership.
DME = Engine Management Computer
Last edited by iansanderson; 04-02-2012 at 08:46 PM.