PCV Valve Check

[pntastar69]

I have 2 plastic PCV Valves. Both of them rattle. I f I blow into the hose barbed end on one of them, it's totally occluded. The other one has a small amount of flow felt. Which one is good?

 

[dadsbee]

Sucks towards carb... doesn't blow the other way. That's the good one.

 

[remytherat]

Blowing from the carb side the valve should be completely blocked if the valve is functioning correctly. This prevents a backfire from pressurizing the crank case.