Which Fram Oil Filter.

I retired from one of the "Big 3" auto companies - worked on engines my whole life. We got our failed engines under warranty back for review to see what we could learn. Obviously you're looking for any type of mfg defects or concerns (typically debris if they were very low mile engines) so changes could be made as needed.

One thing we did was keep track of oil filter brand on the returned engines. There's no way to know the total maintenance history on the engine unless it was serviced at the dealer. So our filter brand sampling is not a perfect methodology for analysis. Nevertheless, when you plot up the failures, you see a natural curve of failures by brand. Let's just say Fram was over-represented in our samples. Leave it at that.

I've said it before that the aftermarket brands have no way to do all the testing and development the OEM's do for their filters. From oil pump relief valve interaction to bypass valve settings to system harmonics, etc, etc, they have no way to do this testing under all the various conditions the OEM's do. The aftermarket guys try to make as many "1 size fits all" as they can to cover as much of the market as they can and to keep costs and proliferation down. This is one reason they are typically way more represented in the failures observed. OEM filters were developed for and with the engines they go on.

That being said, what do we put on these old engines we work on? I'm not convinced all of the requirements have been kept intact for the last 50+ years. But I'm sure not going to use a filter that was over-represented in the failure pool!!