I originally tried a similar thing with the garden hose connected to the hot water tap until it ran clear, I had removed the wheel and the inner wheel arch and disconnected the filler hose from the washer bottle so we could put the garden hose straight into the washer bottle while it was still attached to the car.
It cleared the tank of the gunge but it only really worked for a week or so.
I then found the 2nd video for the 3 Series which was really helpful, the chap who has uploaded the video for the 3 series did not mention the indicator light which is connected the washer bottle.
The cable for the indicator light runs down the back of the washer bottle and has to be clipped back on afterwards.
I took the bottle completely of my car so that I could wash it out in my kitchen sink.
I have edited the photo below to show how small the wholes are on the filters, the other photo is the filter that is in my kettle and I stuck a pin in one of the wholes to give you idea of how small the wholes actually are.
The white filter is about the same size as a dust cap on a tyre valve.
My only other concern was that there seems to be two M6 hex bolts that may fix the back of the washer bottle to the car, when you watch the 3 series video you will see that when he undid the 10mm bolt on the front of the bottle the bottle falls out on its own accord.
I sent a message to the person who uploaded the video with my concerns about the two M6 hex bolts that may fix the back of the washer bottle to the car but he did not reply.
#02 SELF-LOCKING HEX BOLT M6 X 2 “07146961201”
http://www.realoem.com/bmw/enUS/show...diagId=61_1879
When we put the bottle back on the car the bottle located on the two lugs at the back of the bottle with ease and the 10mm bolt on the front of the bottle went back as easy as it came of., I would get someone to help guide the indicator wire back through the whole in the wing to make life easier as it could possible get snagged in the process.
