Hello - can anyone advise where the plenum (bulkhead - where the wiper motor lives) drains are and how the grills come off? I've got water leaking into the footwell during heavy rain which appears out of the heater. Thanks

The plastic grill is held on by screws which are hidden by circular plastic blanks there is a slot if you look closely to insert a screw driver to lever them out.

Leaks into the footwell is highly likely to be caused by failed bonding between windscreen & surround.

Once you’ve removed the plastic grille the drain holes are in the corners and the water spills out inside the front wings. The intake for the heater is at the top of the plenum gallery so the gallery would have to be full of water to get a leak that way.

I use to get a leak from under the dash after moving the car following rain or washing.

I thought I’d cured it with some sealant around the top windscreen seal but actually it was leaking further down , as Mr Teddy Bar says, with the windscreen bonding. In my case poor bonding had caused corrosion at the bottom of the A pillar and this was where it was leaking.
But I think this is rare and probably in https://rover200.org.uk/forums/topic?p=87601#p87601
most cases its the bonding that fails.

Thank you for your replies. I'll check the drain holes first just in case and then move on to the bonding.

Hello Again,

Seems to be the windscreen after all. Daft question - can I re bond / seal or does the glass have to come out?

I believe it is best for the screen to be removed.
You may want to check that the paint is still good under the sealant where the leak is occurring so you don't get any really nasty surprises (i.e rust) in the future around the windscreen framework

Thanks for the advice.