[Formulajones]

Wix filters state they have a bypass valve. Some filter companies just call it a differential pressure relief valve. It's there in case the filter gets clogged.

So I did a quick search to see if others pop up and surprisingly enough it's stated in several articles that most of your paper spin on filters now incorporate a bypass valve. I know the Wix does because I cut those open on a semi regular basis. I haven't cut open any other brand in a long time so can't say for sure.