i had this problem with my GTV. i tried clives method, and it did work for a bit, but then every time it had been sat in the rain, when i drove it, it would tip water on my head
what i found was that i couldn't effectively clear the drain lines using an air line as i couldn't get a good enough seal around the airline to blow the drains through. anyway, i was sorting out the washer jet pipes under the windscreen scuttle one day and noticed a pipe below each corner of the windscreen, these are the offending drain pipes! just whip the scuttle panel plastic bits and you will see them. i removed the ends of the pipes (some sort of funny cone shaped things that had gone a bit hard with age) and then poured water down the drain holes with the sunroof fully open. this flushed a whole load of muck out, and it has been great ever since
well worth an hours fiddling to do in my opinion.
the only downside is that you have to remove the wiper arms, but i used the opportunity to grease evrything up in that department anyway. just remember to mark the drive spindles so you know what position to put the arms back on.
hope this helps mate
After we'd had some very heavy rain recently, I got in to the car after work one day to find that a small fishpond had developed in the driver's footwell, so I thought it was about time I fixed this. To take off the scuttle you'll need a Torx fitting to undo the screws, I think it is size 20. With the scuttle off, the drainage pipes are fairly obvious to spot but I took a photo of them for you good folk. I just pulled the cone shaped things off (The 2nd picture shows them in my grubby hands. You can just see the aperture to allow the water out in the cone that is standing up, it is tiny!
), some gunk came out of the first pipe and warm water came out of the other one!
What seemed rather odd was that the water drains in to the centre of the area underneath the scuttle, right on to the electrics that (I assume) drive the wiper motor - cracking design that!
From reading other threads, I understand that there is supposed to be a hole somewhere in that under-scuttle recess, to allow the water to drain away, although I didn't look for it - I think mine might have been blocked.
This whole area looks like a prime candidate for rust, so when we've had a few dry days, I am going to:
- Take the scuttle panels off again
- Clean the area underneath the panels
- Ensure that the drain hole is free of debris
- Cover the whole area in waxoyl.
Apparently there are some channels for the rear of the sunroof that drain near the rear wheel arches. I'll have a look for them at some point and if I find them, I'll add the details of my findings to this thread.