t2d2

iTrader: (8)

Agreed that compressed air is a bad idea. Those drain tubes are pretty thick, but there's also the risk of rupture if they're backed up bad enough.

I tried the weed whacker approach first and had no luck with it. Too thin and flexible. It basically coils up like a spring when you keep pushing it against something.

Bimmerbill

t2d2
I saw in an old Motors Manual (it's been years ago) that you could use a speedometer cable from a car or truck. In this day and time where would you find one and I bet it would be too short. Just go to Home Depot or Lowes and buy a length of very small cable and wraps the ends with electrical tape so cable will not damage the interior of the drain tube. I know I have repeated myself but if done right this is a very safe procedure. I don't remember how many members of our local BMW sub chapter that have borrowed it and came back to Praise the ingenuity
Bill

KahnBB6

iTrader: (5)

Bimmerbill and t2d2, I had some luck with the nylon weed whacker line but my drains were mostly clear and in my case I didn't have much trouble. I can see why the long metal cable with ends wrapped in electrical tape (or coated and cured in some kind of urethane at the tips) would be a better idea. I defer to both your experience in this.