Since we are part of a 5 store group, we purchase our Wix(Napa) filters in $20K(our cost) shipments that come in weekly. Been doing that since the 80's; that is thousands & thousands of filters sold over the years. We sell to many farmers, city shops, repair shops, commercial users and retail customers. We probably get 2-4 alleged defective filters claims a year. 99% percent are for bad threads. In other words, the end user doesn't screw the filter on correctly or they look at the rolled threads that Wix uses and thinks they are bad. After 28 years and millions of dollars worth of Wix filters, I don't think a couple of leaking filters are bad. I do know that if the proper filter is used, receipts kept, Wix will stand behind any problem. Just another reason to stay with a name brand filter company bought from a locally owned store. Walmart, or many online retailers would just laugh at a filter labor or engine claim. I never have understood someone trying to save a few bucks on a 20-40K vehicle by putting a cheap filter on their car or truck. Your car or truck is your second largest purchase(behind their house); why skimp. Talk to your local store, most run a spring or fall filter sale that allows you stock up and save.
FYI, I used to have over 50 different filters cut apart in one of our stores. It was amazing how cheap the filters that most quick lubes used looked like. Even today, they are paying between .99 and 1.39 for most of their filters. Most of no name filters are now made in China. A Napa ProSelect(bulk pack case) at a $1.69 to $1.80 each is too expensive for them. After having a week off for a vacation, I was shocked to find that all of the cut apart filters had been throw out and the garbage truck had already picked them up. A new delivery driver was told to clean that area of the back room and threw them out thinking they were old filters. I just had to laugh.
Just my two cents,
Dave