Whether it's a thin 0W-20 or thick SAE 50, the bypass valve ensures that the filter media will never see a pressure differential over a certain amount. The media should be able to withstand the pressure differential that the engine requires without rupturing. I suppose that a thicker oil might mean that the filter will spend more time with the pressure differential being closer to the bypass pressure. Of course, a filter being short tripped during the winter may spend a lot of time in bypass too, even with the manufacturer recommend oil being used. From what I understand, Premium Guard filters come from various sources. It seems to be a real gamble as to how good of a filter you will get. Posts like yours are the reason that I decided to try these filters. Your filter media looks really nice.
Originally Posted by sw99
I wonder if it has something to do with the thicker HDEO. I use these all the time with zero issues, Here is one of mine with over 9k miles- https://www.bobistheoilguy.com/foru...