yep . . . does it on both my dad's (03 glx) and mine (00 glx) . . . . kinda like a jet engine sound.
although . . . . you might also be thinking about the secondary air injection pump . . .. kicks in at startup. . . . pretty darn loud. Either way, it doesn't really bother me if i can't hear it on the inside
That is just the sound of the cooling fan.
Most German cars have these rediculously loud a/c secondary cooling fans
My benz is louder than I would like it to be with the a/c on and it has two fans that come.
So the noise that the passat makes is not a shock or a bother anymore but I am hoping the next car I get is not so noisy.
the reason the fan are so loud is because they pull a huge amount of air if you put a sheet of paper in front of the car it will suck it up.