Whats inside the Oil Separator ?

[Mechryn]

So my X5 threw a code the other day for Bank 2 Fuel Trim being maxed out. I looked around and saw that this is generally caused by the hoses on the back of the motor breaking and allowing unmetered air into the motor. I replaced the hoses with some heater hose from the local auto parts store last night. The car seemed to be running fine until smoke started pouring out on my drive home. I read on the forum that this is often caused by the Oil Separator being clogged/broken. I pulled the separator off to clean it and it looks like there is nothing inside it. Brake cleaner freely runs through all 3 holes. If I shoot air into any one hole air comes out of the other 2. Isnt this oil separator supposed to have something in it? A one way valve or something? Why else would you replace this thing and not just clean it?

TIA