When you say the anti-drain back valve failed, can you explain how you came to that conclusion? I would really like to know. AC Delco and Fram?
They are not the same filter. Champion labs makes the AC delco filter. You really do not know what your talking about if you think the E core filter is no good. Do you really think GM would take on the warranty risk of millions of engines because of a substandard filter? Be serious dude. You or anyone else on the internet cannot tell anything about filter efficiency or capacity by cutting a filter open plain and simple. We get letters every day from loyal Fram users with extremely high miles on vehicles that still run fine.