Fixing drains + footwell area.

Pez · 2024-07-18T02:29:21+00:00

Hi Team, Volvo 740 1989 Sedan, Looking for some advice and guidance on how to address my leaky 740. After some digging I found that the plastic wall plate...

jamesinc

Yeah if you lie down and look up you should be able to spot the drains easily enough, there are three or four along the length of the sill.

With silicone, what I mean is generally I'd only use it on parts that originally had a seal that has since failed. If you have mystery water leak from the blower housing, it probably is indicating a drain issue, so if you seal it up, you might end up making it worse. I think use silicone if you think it's necessary but just be sure you have cleared any debris/blockages first 🙂

Pez

jamesinc Cheers mate will do, i understand now. Looking forward to having this fixed up for some peace of mind 🙂

Evan11509

the rust in those photos looks like very minor surface rust... my 740 had a leak coming from somewhere under the dash near the blower motor, and it needed to have a bit of the floorpan cut out and a new piece put in, but yours doesn't look bad at all. I'd maybe have a poke around and see if there are any tiny holes and then just treat it with a rust converter and some sort of rust preventative paint if you want to be really thorough.

Pez

Just an update, it was 100% the failed seal on the plastic cap on the left-hand side of the passenger footwell. Re-sealing it with silicon has worked a treat.

Thanks all.

Baweesh

I’d like to revive this thread because I’m having the exact same issue with my 88 740. When it rains I can see water dripping from above the spout that exits through the firewall when I stick my head under the blower motor inside. Unfortunately it’s covered in soggy sound deadening so I can’t see exactly where the leak is.

Edit: using my garden hose I figured out it’s the seal around the two hoses exiting the receiver dryer next to the emission information sticker. I’ll have to wait until it dries out and I’ll smear it in sickaflex. I’ll add some around the squishy plug that surrounds the drain spout below and just run a nice bead to seal the blower fan shroud in the cowl.

Baweesh

Baweesh An update, I thought that I fixed the water leak issue but we had some rain in Brisbane over the last few days and I could still see water trickling down the corner of the passenger floor. You can see a trail of this brown dust which I believe is old disintegrated sound deadening coming from behind and above the blower fan housing. I suspect the windshield may be leaking. Can anyone tell me if they’ve had a similar issue?

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carnut222

Have you removed the metal air inlet panel below the windscreen to investigate in there? The inlet for the heater box has like a plastic air scoop on it and i think it has a seal around the bottom to prevent water getting in around that area. Also look for trapped leaves etc. Could also be the windscreen as you mentioned. Sometimes these can be difficult to track down.

Baweesh

carnut222 I have indeed removed it and I’ve resealed the plastic shield over the air inlet. Annoyingly i spent an hour spraying the window, cowl and vents, inside the engine bay and even in the wheel well with a hose and not a single drop of water made it through. Only seems to happen when it rains.

Major Ledfoot

Isn't this the bottom of the fan motor?
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Is the incoming water intruding via this hole?

If so, IIRC that ought to have some sort of hose attached to it, where it drains water from the bottom of the fan motor to the cavity under the A pillar. (Sorry, it's been that long since I've had a 740 and IIRC the 940s have a different fan motor, so memory might be playing tricks on me).

carnut222

Major Ledfoot I think it is the heater fan case drain - see this pic here - looks like the rubber hose has been removed in the later photos. The hose should run over and drain out through a hole in the dash panel IIRC.

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Baweesh

Major Ledfoot Yes I have removed the fan and the drain hose, I spotted it leaking after driving in the rain with the fan and hose installed so I don’t believe it’s that. I can see your concern though because the photo does make it look like water is dripping out of the drain hole.

Major Ledfoot

Baweesh I can see your concern though because the photo does make it look like water is dripping out of the drain hole.

Yeah, that's what it appears like, since the water stain in your pic is about halfway down the length of the plastic cavity plug that goes into the cowl under the A pillar. IIRC there was a service bulletin and mod done to the 740s for the fan drain, but I forget what year model it applied to. The pic which @carnut222 is the setup I recall seeing in my 740s.

Noted how you're not getting any leakage into the car when squirting it with a hose. Is the leakage occurring after driving in the rain, or by the car sitting in the rain?

Baweesh

Major Ledfoot I spotted it after driving in the rain. I’ll try and get a photo of it when it’s wet

Baweesh

Baweesh Update, I ended up converting to a 90+ style blower fan, and I can confirm that water is getting into the blower motor area and leaking from where the fan assembly seals against the fan housing box. It seems to only leak after a decent amount of rain, and this happened whilst the car was parked.

Does anyone know how to prevent water from pooling inside the fan area? I’ve cleared the drain hose in the firewall and I’ve sealed up the plastic cover up top. I’m a bit stumped.