That is the PCV circuit. It starts at the crankase filter then runs to the PCV valve, the round thing, and then into intake.
You probably have a PCV valve that is stuck open. It is supposed to move so it does not suck oil into the intake.
You can either clean it with brake cleaner until it moves freely, you can tell by shaking it, or you can buy a new one.
March, 29, 2012 AT 12:34 PM
If the engine is in bad condition with excessive blowby, the PCV valve can't help much. You would need to rebuild the engine to rectify.