Is there supposed to be a hole in the middle of the airfilter case like circled in the picture? Seems that dust etc could get past the actual filtering process this way...

And one plastic hose broke off when fiddling around there, it goes to the red circled area on the left bottom and to some sort of valve under the airfilter cover. What is the function of this vacuumhose and valve? Anybody got the partnumber for the new plastic vacuumhose? (whiteish/blank color)

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99 W210 E220 cdi sedan automatic (248.000 km) 210.006