Rainwater leaks - standard locations?
 

Hi all,

For far too long, I've been putting up with rainwater getting in and making the carpets damp on my 1989 740 estate. (It's not the classic heater valve leak - already checked that.)

It seems to affect floorwells on both sides and, on the odd occasion, I've had a couple of drips fall from where the headlining meets the top of the windscreen when setting off on a journey but I suspect that might just have been coincidental condensation as it didn't carry on doing so even in heavy rain.

Last year, I tried running some silicone sealant around the top and sides of the screen after removing the chrome trim. I've had the scuttle panel off and checked for holes in the bulkhead. I can't see where it's getting in.

The fact that it affects both sides suggests it's somewhere that could run to either (or both) sides rather than something like a door seal which would affect just that side (unless both door seals have given up, though that seems unlikely, as the passenger side doesn't get that much use anyway.

Has anyone got any suggestions for standard locations to check? Is there somewhere that they always seem to go?

Winter is here and the heater on this particular car has always had a fairly restricted effect (especially compared with my 940 which is like an oven when on full) so it's often difficult to keep the screen clear with so much damp in there and I'm also concerned I'll have rotted the floor out if I don't get something sorted sooner or later!

Thanks,
David.

has it got the little flappy door vents in the footwells?

On the other 740 my dad had, I once found water dripping from under the floor pan and found the passenger side carpet totally sodden. I seem to remember taking the footwell panel off and removing and resealing the little duct that sits in there, I think it leads to a void behind the front wing.

Oooh! That's an interesting possibility as the butterfly spring fell off the one on the driver's side straight into the hole and was lost, so it flaps open and shut all the time ... though surely there shouldn't be water floating about inside there anyway? (I'm not sure whether there's one on the passenger side. I have a feeling there isn't.)

Good point, though. Mind you, I'm not sure what I can do about it if it is getting in there. What exactly was it that you re-sealed?

Going back a few years now, but I think there is some form of plastic 'deflector' which pushes into the hole in the foot well with a rubber or foam seal around it. Seem to recall sitting in the car in the pouring rain to try and find the leak.

And / or a sunroof? The seal on mine hardened with age and no longer prevented the ingress of rainwater, especially in heavy rain. Coupled with blocked drains, water can 'track' inside the car such that the point of entry is not always obvious.

If possible, I'd get someone to play a hose over the car while I sat inside looking for any leaks, especially around the doors, windows and sunroof (if fitted).

Regards, John.

Mine definitely has a leak somewhere around the top of the windscreen. I haven't pinpointed it exactly, but I know there's corrosion. Once inside, the water runs down behind the A-pillar trims. At some point I plan to get the screen removed so I can sort it out properly.

Mine also had a leak where the A-pillar, toe-board/bulkhead and inner wing come together (there's a flange that catches all the spray coming off the tyre full-on). I recently welded that, and hoping the MoT man is satisfied with my welding.

The footwell vents are supplied from channels in the inner wing that get their air from the ends of the scuttle. They double as scuttle drains, but they're huge. They drain into the sills, by the way, and should drain out through the sill drain slots.

Sounds like I'm going to have to find a way to get my head under the dash by the flappy vent and have a good look. (Not so easy with a frozen shoulder, back trouble, knee trouble etc! I seem to be suffering from more than my fair share of 'tempus fugit' :tounge_smile: <sigh>) It would seem to be a bit of a coincidence that it's doing it on both sides, though.

I forgot to mention that it doesn't have a sunroof, otherwise that would certainly have been a prime candidate! Good call, though.

I've actually just wrapped my hosepipe up for the winter now that the frost has arrived but, yes, that is probably the best way to find it... if I can borrow a friend to help me that, sometime.

I don't think I'll be doing anything in the next day or two, however, given the weather forecast!

I did wonder about the screen, though I also bunged some sealant round it a year or two ago, to no avail.

I also had a poke around in the channels when I had the scuttle panel off to replace a broken bowden wire on the wipers and I couldn't see any blockage that might be causing it - everything seemed clean and free of holes etc. As you say, they're more like small canals than drains!

I know what you mean about that wheelarch - I had the same area welded a few years ago and it still seems to be well sealed so I don't think that's it - this fills up even when standing if there's been rain for a few days when it's been sitting doing nothing, rather than only when driving spray hits the arch.

Snap! I know that on mine, the water emerges at the bottom front corner of the door seal (same on both sides) and from there into the footwell. The question is where it's going before it emerges. I did think it was the seals, and I've tried removing them, cleaning them, using silicone spray to pep them up, and silicone gloop to seal the seal to the flange that it clips to - all to no avail. Further investigation is needed.

I haven't looked carefully at the corrosion around the windscreen header yet, beyond to note that it's there. Nor have I tried to seal it yet - mostly because I was trying to do the same task on my Disco, and I couldn't face tackling the Volvo at the same time! I thought I'd fixed the Disco's screen leak using Tiger Seal. I now know that I didn't succeed!

So the status quo is that I have two project cars, both with leaking screens, both of which probably need the screen out for a proper fix. And it's November and cold and miserable out... Hey-ho!

Hang on - are we at crossed purposes? I was meaning high up in the rear of the front wheelarches which (I think) is quite a lot forward of anywhere near the door, as the flappy air vent must be to the rear of the arch and that's well forward of the door too.