I have finally located where water is leaking in my 86 760 turbo. In the foot well, drivers side there is a black rectangular piece of plastic with rounded corners (6" x 6") on the left side where it appears a vent would /should be however this cover or whatever it is does not move or open and there does not seem to be any louvers for air to enter. What the heck is this for and what is the best way to seal it? What a stupid design!!

I haven't seen the 760 but the later 240s have a similar opening closed off by a metal plate. Some models had fresh air vents in this spot. In fact, my '88240 did not have a vent (it had AC). I went to a pick and pull and took a vent off of an olde240 and installed it in place of the metal plate.

You can seal this with body putty which I bought at an auto paint store or just use urethane caulking which is better than the silicone which would probably also work.

Thanks, I spoke with a Volvo service guy who knows little more about this than me. I was hoping for an easy quick solution where I could simply pop the cover off...NOT. He suggested using a product called Dum Dum which essentially sounds like a urethane type of tape that can be molded into place. I would have preferred to seal the leak from the outside of the cover where the water comes from however I guess I will give that a try before the next rain (here on the Canadian wet coast)

That Dum Dum stuff sounds like the body putty I refered to. I'm with you about prefering to seal from the side where water gets in. It's too bad you can't remove the cover and seal it. I wonder why it won't come off.

I live on the US "wet coast" in Oregon. Our Republican freinds call it the "Left Coast". HaHa