Air Cleaner

[oj88]

i'll just file it under "one-way valve".

Generally speaking, yes. Technically, no. It should flow unrestricted in one direction and slightly restricted in the other. How slightly restricted is dependent on the intended use. The engine vacuum varies widely during operation and certain pneumatic devices controlled by vacuum needs just the right amount to work properly.



Somebody can probably explain it more eloquently:

In one direction the VTV's are supposed to restrict, but NOT prevent flow. In the other direction, it should allow unrestricted air flow. If the flow one way is stopped, then the emissions system the VTV is associated with won't work properly.