a bad cyclone (the Crankcase Ventilation Valve) is possible...since the engine is an M52, this is the P/N
11151703484
it can be replaced without taking the mani off
http://www.dvatp.com/bmw/diy/icv_ccv/
look at the oil....it s milky...look at the coolant too, if it is milky too, it s a bad HG more likely than not........I've never done one but it s a time consuming job that requires special tools that can be simulated
Patter$on is right there....milky cap can simply be moisture from sitting
no coolant journals in BMW intakes