Looks like my repaly was blocked again. So here goes cut and paste.

PCV=Positive Crankcase Ventilation.

This is the method of extracting piston blowby and other fumes from the crankcase for many vehicles. Note the Vanagon does not use a PCV system. It is basically an open vent leading to the engine intake between the air flow meter and throttle. The job of the tower is to let some of the liquid separate and return to the crankcase.

A PCV system usually consists of some type of metering device that connects under the throttle plate so that so that especially at low speeds the blow by and stuff is actually sucked out and fresh air pulled in.

Dennis