I used to be an exclusive AC Delco filter only user. Than I had 2 fail on me. Never again. Some may recall my posts about it - I basically had no oil pressure at start up. Would happen at every start up and you had to rev the engine to get the gauge up. Change oil filter -problem gone. Put old one back on - problem back. Both times this happened, the filters had less than 3k miles on them. NEVER happened with any other filter used after that. Bosch, ST and STP filters now used with no problems. No more AC's for me. The filter in question was a PF46 for my GMC Denali pickup with the 6.0L engine. It happened twice - not once - twice.