2006 Volvo S40 T5 weird coolant leak, need help identifying a part

[Electronicsguy]

This car has had a coolant leak for several months but we were just adding coolant once a week. Now it finally got bad and I can see where the leak is. I also see some oil in that spot too but the coolant is running out of this spot as fast as I put it in even with the car off. It's on the driver's side of the engine near the top. There is a round opening and I can see the metal disc rotate when the engine is running which makes me thing there should possible be a cover over the round opening? Maybe that's also the leak issue or maybe coolant shouldn't even be in there and it found it's way there because of a pcv or turbo issue? I attached a pic. Can anyone tell me if this should be covered and sealed and normally have coolant behind it or is that where it just happened to find a way out? Any help would be appreciated. Thanks