Re: 528e dash vent is clogged with leaves
If you are talking about the dash vent, slide a small flat screwdriver between the outer frame and the vent and carefully pry it out. This should allow you to remove the vent and vacuum it clean.
I can't imagine how leaves can get past the hood plastic inlet grill (the ones besides the washer fluid nozzles), through the fan inlet(that has more grilles) and the fan itself. You might want to remove the heater fan cover and clean the interior cavity. This is the big black cover behind the engine and is held in place by about 6 to 8 small screws and the hood seal (just pull it up to allow it to come out).