Hunting Down Leak Under Dashboard, Passenger Side[96 850]

[scot850]

As Abscate says, it is more likely from the windshield area. Where you park your car, how does it sit? To LH or RH sides and nose down or up?

Neil.

[ToriWhite]

Update:
Tested drains, Sunroof drain works fine. Interior cowl secondary drain works fine.

That’s really a position for a windshield leak rather than a dash cowl leak

I have an extra filter housing if you want it but I’m in NY. In Riverside next week!

Thanks, but I'm not too worried about the missing cabin air filter, so much on the todo list of more pressing stuff needing my attention that it'd just collect dust in my closet, instead of yours haha

As Abscate says, it is more likely from the windshield area. Where you park your car, how does it sit? To LH or RH sides and nose down or up?

Neil.

I couldnt say without a level on hand .. I mean it *looks* flat and even L/R, if anything maybe nose heavy, but if I had to bet on any L/R unevenness I'd wager on drivers since that's the heavier side if memory serves.

I tried pouring along the passenger side trim of the windshield, and down along the lower corner of that side.. nothing appeared to be 'wicked away'.. but that doesn't mean there's nothing there. The leak intensity was very weak and low volume, and pinpointing it was a task despite doing so in a downpour. This could be because it's a small leak that won't catch a visibly appreciable volume of fluid just pouring water, and will only 'start' under sustained downpour.

At least got a layer of cat litter down there on passenger side, and weather doesn't look too rainy for the next few. Barring any other suggestions, I think the windshield leak is most probable. I've already got a couple todo list items for taking the dash up, so I may pull that up and take a peek what's going on

[ToriWhite]

In prep for removing the dashboard, figured I'd watch some vids for insight. Is anyone aware what this feature is that white blower motor mounting bracket is bolted to? If I'm extrapolating correct, whatever is underneath that insulation layer; that hollow thing is the thing that is somehow getting wet on the inside.

[scot850]

Hard to tell. The material is just a sound deadening material. That white 'snake' on the very RHS looks like a wire harness sleeve. Do wires come from the engine side through the firewall near that side?

There is another possibility I hadn't thought of. I read about it a few weeks ago. Do you have a wagon or a sedan?

Either way, under the roof trim that runs from front to back, there are clips under the trim holding it in place. There are screw holes under there and they have what looks like strips of thin tar paper to seal them. They were designed for roof rails (not sure if the sedans have them) and the mounting screws go through there and 'heal' themselves. Over time the material breaks down and can cause leaks. Long shot.

If your water is coming in up that high the only routes are the windshield seal (mine was leaking at the top) top, side or bottom. It will then run to one side, but if it was the top, I'd expect the driver's side to get wet too. So that would reduce it to side or bottom.

You don't have any rust under the top seal or around the windshield?

Otherwise I am running out of suggestions.

Have you tried a hose-pipe and focusing the jet at specific points along the windshield?

Neil.

[ToriWhite]

Hard to tell. The material is just a sound deadening material. That white 'snake' on the very RHS looks like a wire harness sleeve. Do wires come from the engine side through the firewall near that side?

That big tangle of wires comes from the center console, touch base on the resistor pack + blower motor, and then if memory serves, goes into the side panel. I'll have to double check, very likely some branch upwards as well. I remember first thinking it was trailing down off the wire harness, but after first feeling about down there thoroughly, I think it's unrelated.

There is another possibility I hadn't thought of. I read about it a few weeks ago. Do you have a wagon or a sedan?
Either way, under the roof trim that runs from front to back, there are clips under the trim holding it in place. There are screw holes under there and they have what looks like strips of thin tar paper to seal them. They were designed for roof rails (not sure if the sedans have them) and the mounting screws go through there and 'heal' themselves. Over time the material breaks down and can cause leaks. Long shot.

A manual 850 sedan. Wish it was a wagon, though.. The sedan roof is featureless except for the accent trim along the border, and the sunroof.

If your water is coming in up that high the only routes are the windshield seal (mine was leaking at the top) top, side or bottom. It will then run to one side, but if it was the top, I'd expect the driver's side to get wet too. So that would reduce it to side or bottom.
You don't have any rust under the top seal or around the windshield?
Otherwise I am running out of suggestions.
Have you tried a hose-pipe and focusing the jet at specific points along the windshield?

I do have a smidgen of rust on the top center of the windshield, from what I assumed that was from being an exposed lip that got chipped with road debris and lost its protection. I haven't looked but that very well may be an encroachment point.
I've seen in my research many people who fall under the case of 'water down the A frame, dribbling down the footwell wall onto carpet" but no other case of something from In the dashboard

I'm in a rental, and have never found the need for a garden hose, but I guess its time to splurge at the dollar store for the sake of diagnosis. Thinking of volunteering my sibling to monitor dampness while I slowly work way up from bottom corner to top along the edge.

[abscate]

The big white hvac system is a large unit that has to come off in one piece , there are lots of pictures of this in the Fora


That rust spot is almost certainly your water intrusion point, that all fits. But, rust in Davis? That’s really strange.

Bunch of pictures from my early days on MVS in this thread, 11 years ago!

viewtopic.php?t=56005&hilit=1999+v70+t5&start=30

[ZionXIX]

If you are going to pull the dash board, consider opening the Hvac tunnel and cleaning out all the crud that has built up over the years. I would be interested to see the it looks like inside where the condensation drains. I think you can operate the vehicle without the dash in place while you figure out where the leak is coming from.

[ToriWhite]

viewtopic.php?t=56005&hilit=1999+v70+t5&start=30

Thanks for the link and pictures
If my sense of depth and orientation are correct, I think this may give a good illustration as to what the Wet Spot is. On my volvo It feels like the under side of a metal surface with holes, covered with fabric, and this looks like it's in the same location and also appears to be a metal structure with fabric on the underside, and it's underside may have holes.

I think now I need to pull the dash off first before spraying the car down, to see the afflicted area to properly diagnose, given it's all one long metal square tube- area getting damp may be because its the only/lowest section with holes on the underside- and that the ingress point is elsewhere along that tube

[ZionXIX]

This is a crazy idea but you could drive the car without the dash in place. Go to the drive through car wash. That's the most water pressure you're going to find without rain.

[scot850]

Might be hard to drive the car without the speedo cluster that is held in place with the lower dash panel. Also you would have to refit the steering wheel, and turn signals at least. Add to that with the upper dash off it will turn on your airbag light as the passenger airbag is not installed, so you will need to be able to switch that back off.

The thought is sound to be able to get enough water. However, I would suggest a hose is better as you can direct it to specific areas to test while the car is disassembled.

If you are going to pull the dash and heater system, you will need to disconnect the A/C evaporator. You may want to spend the money on replacing that while in there. It will likely be corroded as the bottom, especially when not having had the cabin filter in there.

Neil