My drivers side sunroof front drain is blocked leading to water in my footwell, screen pillar etc.. I have so far tried some nylon fishtape, including with a sharpened brass end, and a steel coiled drain clearer, with a fair amount of force, twisting, pulling and shoving with no result. The blockage will not budge and seemes to be towards the lower end of the screen pillar, judging by how far I can get the tape in (goes 2 or 3 times as far on the passenger side which is not blocked).

I have also pulled back the wheel arch trims and can't see anything blocking the drains on them, the engine bay drains all work.

Have also tried sucking and blowing with a vacuum cleaner. Not tried my air compressor yet (might it blow off/rupture an internal hose?).

Can't think of anything else to try. I could put some drain cleaner down but would worry about what damage it might do to steel, aluminium, plastic and paint.

 

I used 6.5 trimmer line with some lithium lube in both sunroof drains. It went down quite a way. but I didn't measure the amount. In the future I'm going to measure and document both sides as well as other drains in my maintenance log so in the future when I push the line in, I can compare and see if there is something blocking it. I would recommend getting a small funnel and using degreaser or vinager or even lye drain cleaner in small ammounts to dsiolve whatever is in the lines. I need to lookup WIS to see if there is something about this. Good luck and please update. I can't imagine the cost of replacing the drain pipes. Sounds scary.