If not there now, you can get vented covers from your dealer as Volvo makes them for S80s. It's part of a used car upgrade package done to certified '99 S80s and I'd think an '01 would already have them but I've never checked. If you have them now, they're installed on the two high beam lamps (closest to radiator) and the covers have a screen like section in part of it. Remove the high beam bulb covers and see if you now have those and if not, get them replaced.