Originally Posted By: blupupher
Originally Posted By: ZeeOSix
Depends if they are formed well or not. Filters with louvers should be inspected before being installed.
Exactly. Louvers in and of themselves are not bad, just when shoddy manufacturing happens and they are not opened up as they should be.
+1 ... I like the design of louvers, but I don't like the fact that shoddy manufacturing can happen much easier with louvers than with holes. We have all seen some examples of bad louver forming in this forum, and that's where the photos I posted came from.
I looked at some of the newer style Purolators at the local store a while back, and found quite a few with what I'd consider bad louvers - many of them were barely opened up. If I look down inside a filter with a louvered center tube, I want to see them all well opened up like the example I posted above. I don't want to guess if there is adequate louver area or not when I see louver slits barely open.