AFAIK, the STP filters are still built with metal end caps and steel pressure valve springs.

The FRAM filters, OTOH, use bonded cardboard and plastic valves. :eek4:

I've heard of two separate incidents where either the valve failed or the cardboard delaminated inside a FRAM filter. One caused severe oil pump damage when the filter medium was ingested.. The other (by clogging the pickup tube) starved the motor out of oil long enough to cause serious bearing damage.