PCV System
WARNING: This page is about a different car, the 2010 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
The PCV system uses intake manifold vacuum to ventilate blow-by vapors from the crankcase and return the vapors to the intake manifold for combustion. The PCV valve varies the amount of blow-by vapors returned to the intake manifold based on available engine vacuum.
The PCV valve on the 4.6L (3V) engine is integral to the LH valve cover. If a new PCV valve is required, a new valve cover must be installed. Refer to ENGINE - 4.6L (3V) .