Originally Posted By: Joenpb
The filter is worth the money if you go 10k+ miles on a OCI. I wouldn't want a cellulose filter for anything over 7500 miles, some not more than 5k.
That's a fair statement. What you "want" is based upon emotion.
I, too, want things. I want knowledge and understanding.
I "wanted" to know how well "normal" filters would hold up; how well do cellulose filters really do under "severe" and "prolonged" circumstances. So I ran some testing.
I took a WCOD (Purolator) and ran it 10k miles on my wife's van; she drives "severe" per the manual's definition. I ran the 10k miles on ST dino 5w30. Upon the end of that OCI, I got a UOA and did a filter dissection. Everything was perfectly fine. So I then did another trial at 15k miles; this time on a FL400S (not correct application, because it has a BP valve and the car has one in the block already, but no harm is done having two). Again - ST dino oil. Again - absolutely "normal" products under "severe" circumstances. UOAs and filter tear-down showed absolutely no issues whatsoever. In both filters, the media was fine after running out to 5x the "OEM severe" schedule. There was no voids or tears in the media; no bunching or collapsing. Photo links are posted on this site as are the UOAs.
I've also run cellulose filters for up to three years on my Dmax, just shy of 10k miles. Filter was rusted a bit on the outside, but upon cutting it open, was perfectly fine inside. The media was firm and held up extremely well, despite the age. Photo links and UOAs posted here at the site.
Additionally, when Jim Allen visited the Fram tech lab, one specific question he asked for a non-binding answer is just how long can a filter be left in service. Three years? No problem. Four years? Probably OK. Five years? That's when the "tooth sucking" (his words) started to get "iffy".
Also, many brands will warrant their filter up to the OEM OCI limit. For example, in some Asian models, that can be pretty darn long. My daughter's 2000 Galant shows the "normal" OCI of 7.5k miles, and the owner's manual clearly states that one can change the filter every other oil change. So 15k miles (even on cellulose filters) is doable by the OEM criteria, and because it is the OEM defined limit, then by default all the filter makers would warrant their products to that recommendation OEM limit. Ignore the marketing hype on their lead web pages, and go straight to their warranty statements, because THAT is where the rubber meets the road, so to speak. If you follow the OEM guidelines, then the filter makers are generally accepting of those limits as their own, because they make the filters to perform to the OEM criteria.
Now, there's nothing wrong with you "wanting" to hold your filters to some arbitrary limit if that makes you sleep well at night. And if you had evidence that cellulose were failing repeatedly at short exposures, then I'd be willing to take notice. But of all the failed filters posted here, very few (if any at all) had failures due to some arbitrary limit that was exceeded simply because they were cellulose used to 7.5k+ miles. While I whole-heatedly agree that there is some practical limit for each filter design, I cannot immagine that your self-imposed 7.5k miles is anywhere near the true capacity limit for today's quality filters. Sure, some junky, low-dollar filters would be a risk, but not a Fram, Wix, Mann, Baldwin, etc. The tears/holes that we've seen in Purolators are disconcerting, but there's no ability to know how/when the media failed, so why put an arbitrary limit on such an unknown?
