Possible leak from windscreen

[Laird Scooby]

The ECU shouldn't be rusty brown. I'd be removing trim above it to see if i could find water marks and try to trace the ingress point that way.

[frielp]

My carpet is getting soaked again last time it was definitely the windscreen even though its bonded.

[Delta66]

Originally Posted by Laird Scooby

The ECU shouldn't be rusty brown. I'd be removing trim above it to see if i could find water marks and try to trace the ingress point that way.

This shows that there is no problem with the ECU, the plastic end is that colour;



I have already removed trim and checked that part of the car. There is no sign of water ingress and any paper towel left there has remained dry.

Indeed, the paper towel spread about the floor and under the underlay, even after last nights heavy rain is completely dry.

[Laird Scooby]

I did say it was difficult to make out exactly what it was. IF there's no sign of water marks on it then you need to look in a different place for the water ingress.

[Delta66]

At the moment there are no water marks or signs of ingress anywhere.

It is as if someone poured a bucket of water into the foot well and with the cold weather it has just been very problematic getting it to dry out.

I know for a fact the foot well was dry about 3 weeks ago, as I keep a bit of kitchen towel under the mat and on top of the sound proofing and it was dry then. I do a Sunday check of oil, coolant and foot well due to previous issues with all three.

The wet appeared after two days of snow a few days of ice (ending when I took this photo of the ice sliding off the car)



There has got to be a connection. When it rains (and using a jet wash), no water ingress. After snow and ice melted, water appeared.

[Laird Scooby]

There are scuttle drains below where the vent is just in front of the screen. They're usually found on the bulkhead a bit further down than you'd expect. If one (or both of these are blocked, the intake (which is the vent) can fill up with snow and it won't run out of the drain because it's frozen, however it will thaw out as the heat from the engine gets to it. If it can't get out of the drains because they're full of (still frozen - don't forget heat rises) snow it will find it's way through the heater box and into the footwell - had this on a number of cars.

It's a possibility, i know Volvo sell snow caps for models with the vents in front of the screen/behind the bonnet, perhaps to eliminate this problem.

[Delta66]

Originally Posted by Laird Scooby

There are scuttle drains below where the vent is just in front of the screen. They're usually found on the bulkhead a bit further down than you'd expect. If one (or both of these are blocked, the intake (which is the vent) can fill up with snow and it won't run out of the drain because it's frozen, however it will thaw out as the heat from the engine gets to it. If it can't get out of the drains because they're full of (still frozen - don't forget heat rises) snow it will find it's way through the heater box and into the footwell - had this on a number of cars.

It's a possibility, i know Volvo sell snow caps for models with the vents in front of the screen/behind the bonnet, perhaps to eliminate this problem.

Out with a watering can and 5l over the screen at the A pillar, waited an hour and nothing. Another 5l into the vent below the screen (which promptly emptied out below the car, all the way to the back passenger door) waited an hour and still nothing.

It is till bone dry inside, so that freak weather of snow then freeze must have done what you suggest.

I will let the underlay keep on drying and refit and if it snows again, I will clear the screen and vent rather than let it melt.

[jpliddy]

might be best to drive the car for a good few days with rain and snow on the way
before putting everything back a few days here and there is better than the dreaded wet carpets i know from my problems i left it for a while before finding my leak

[Delta66]

It snowed last night and then melted today with no dampness inside.

With cutting a hole in the carpet and soundproofing, I will be able to remove it and the lining without having to take off all the trim, if it happens again. It also means i can check it regularly to make sure it is staying dry.

The plan is to refit everything tomorrow and go for a drive.

Thanks for the advice and encouragement. I would describe myself as a cautious mechanic who likes to check and recheck before I do any work!

[MiniNinjaRob]

I had leaks in my 940 and I went through all the checks I could find on the internet.

First you’ve got the footwell vent.
Then the heater vent - you need to remove the scuttle and check that water doesn’t get into the air vent - have a look at my car thread and you’ll see what I did.
Then I checked the sunroof drains, these were ok.
Then I checked to see if there was any issues with the bulkhead - mine is a later AC car so I think that’s why I didn’t have a problem in that area but IIRC the non AC cars are different.
Then check the sunroof seal - mine was ok.
Then check the seal between the glass and the rubber on the sunroof - mine wasn’t good so I sealed it up properly.

When I did each of the above it improved things bit by bit until now when I don’t get any leaks at all. I just needed to check and repair all the common issues (which aren’t all listed in one place!) until it was sorted.