Originally Posted by Vigilant
... After reading several threads on oil filters, I'm no longer comfortable running an FL820S to 8000 miles, because it might go into bypass mode at some point.
If you want to use a FrU, then by all means go for it.
Your fear regarding the FL820 going "into bypass mode at some point" is completely unfounded.
I offer two reasons why ...
1) Ford ran their TCB testing back in 2006 using 4.6L engines in some taxis in Vegas; they ran the oil/filters out to 15k miles and saw no issues whatsoever about filters going into bypass. While filter bypass was not the test mantra, they did note that wear rates continued in a downward trend as the OFCI went longer ... all the way out to 15k miles. So it is fair to presume that the filter was not going into significant/sustained bypass or the wear would have trended up, and not down as it actually did.
2) our member Jim Allen did testing on the same filter; he using some well integrated high qualify pressure tracking equipment where he follow the dP across the filter. He never saw the filter go into bypass except for using oil that was too thick, and revving the stone cold engine far past a sensible point (WOT bursts on a cold engine). And even then the dP was only for a couple seconds. When the oil was warm and of the correct vis, there was never any bypass whatsoever.
Additionally, I've run repeated runs of 10k mile OFCIs, and some out to 15k miles, and after countless good UOA results and boring UOA filter dissections, I see no basis to believe any filter blinds off and goes into perpetual bypass in a normal application. Today's engine run too clean, and lubes are so well fortified, that filters blinding off are a silly debate. No filter goes into BP with any frequency. Unless you're engine is in horrifically dirty shape, and you have sludge in massive amounts that would blind off a filter, there's no reason to ever believe a filter is going into bypass in any dangerous manner. Not ever.
Now, if your fear is based on the potential of torn or voided media in an FL820, that might be a different conversation.