Great, its designed like that but on P38s this vent pipe is badly positioned because as the cooling system starts to vent it does so where there are electrical connectors etc, in the pictures you'll notice two connections and if you separate these (depending on age) you're sure to find corrosion as I did on mine.
These connectors are various inputs into the engine ECU and could give a bad signal.
The mod is very simple and takes around 2 minutes