Fram Endurance / Walmart End of Life ?

[ZeeOSix]

All but one of the FRAM Ultras represented in that table are the older OG Ultra with the full synthetic media. The one other particle count I've seen for a newer synthetic blend Ultra came in ISO at 13 (>14 um), 2 ISO codes lower than this leaky filter. That PC was from 2023, so maybe before the leaky end caps became common. Still, there's not enough data to say for certain if this was due to the leaky end cap or just random variance.

It could be any filter with a metal-to-metal "sealing" interface could have some level of leakage, and obviously if the leaf spring stamping is bad with ruffles and warpage, then it could vary all over the place depending on the manufacturing quality the day they were stamped as seen by the different levels of that seen in C&Ps. The only way a metal-to-meal leaf spring interface it going to seal the best is if the leaf spring is nice and flat and very smooth where it seals on the raised ring around the center tube on the end cap.

Here's an updated table. I included another table with particle counts for filter models that I only have one particle count for.

View attachment 290528

What would this data look like if the lower ISO 4406 codes were compared?