Assuming this is a six cylinder engine here. Is this oil getting into the air box? These special PCV valves look like a bandage fix. Oil blow by in the air box is cause by a combination of possible bad gaskets or hoses. It can be caused by the valve cover gasket being bad, the grommets around the breather/PCV, or possibly the holes being worn. This allows an extra rush of air through the ventilation to lift particles of oil out of the lifters and into the air box tube.