I tried my first Wix cartridge filter in my 09 Hyundai Santa Fe 3.3l. I had previously only used OE Hyundai filters. I used the same oil I've been using, MC blend 5-20. First start up the next morning it sounded like someone was rapping the valve covers with a hammer! Even hot starts hours later produced noticeable knocking on start up. Today I couldn't take the 3 days of start up knocking and I replaced the Wix with an OE Hyundai filter. I Let the car sit for 6 hours and it was back to it's usual quiet start ups. I did compare the two filters when I changed them out. I didn't really see any big differences between the filters. The only thing I noticed was that the one small o-ring that comes in the Hyundai kit was beefier then the small o-ring that came with the Wix filter. I believe that o-ring is what forms the seal in the drain back system. The smaller Wix o-ring probably let the oil drain out of the housing causing the start up knocking. Anyone here ever seen this issue before?