Fresh air would be drawn through the breather tank and down through each valve cover then out the valley of the engine, via the vacuum signal on the intake side of the PCV valve. See All 20 Photos 1.

Why do my valve covers persistently display oil around ... engine with a closed PCV system (where the crankcase breather connects to the air cleaner base). Side effect #3: Excessive blow-by ...

The problem is that it is spitting oil into the breather through the valve cover tube. Is there a cure ... forcing oil into the breather element and air filter housing. Q–In your column ...

Imagine one day, years ago, in some equipment shed out in Middle America, an innovative farmer looking at oil dripping from the bottom of the well-seasoned 5.9L Cummins engine in his Dodge Ram ...

The air removes the stored gas fumes from ... the rubber grommets that seal the PCV valve and the breather pipe to the valve covers. When these harden or crack, fumes can escape and dirt can ...