I had recently cleaned my very clogged oil trap/breather box and just now noticed there's a slight vacuum in my crankcase at idle! When I pinch closed the vacuum line that goes from the breather box to the throttle body, there's no vacuum when I open the oil filler cap, and light smoke wafts out from the filler hole. And yes, I hear my timing belt tensioner pulley assembly. It hadn't been started in weeks, that's the next service item. Stay tuned for that video.
Saab, 9-5, 3.0t, PCV, Crankcase, Vacuum