Fresh Oil filter Every time?

[SARG52]

Lots of silly stuff.
Heard of fleet owners that leave the oil and just replace filters.
Seems to support the expression "Common sense is rare".

 

[KCJeep]

What do you think when you cut and paste it and you have a Tearolator? Did it happen at 5,000 miles or at 65,000?

Nobody knows for sure, probably a combination there of, but during the Tearolator heyday there were some pretty low mileage filters with tears posted.

 

[ZeeOSix]

I can see this happening if the bypass opens or a very large pressure increase

That's something different. The filter media can become less efficient without the bypass valve opening. You'd have to go read that thread I linked to earlier to understand the difference between the media losing efficiency from loading, vs the filter bypass valve opening. One of the main reasons that some filters show a low ISO 4548-12 efficiency is because they lose a lot of efficiency as they load up. The ISO efficiency rating is the average of the filter's from new to nearly fully loaded - in other words, when the filter is 50% loaded to full holding capacity. So oil filters that have a high ISO 4548-12 efficiency don't lose much efficiency as they load up.

Here's data from an ISO test showing how this oil filter's efficiency dropped as it went from near new to near fully loaded. The efficiency at 20u goes from ~85% at 15% loaded to ~53% when is 65% loaded. The particle count data above 65% loaded saturated the particle counters. The 100% loading level would be considered the full holding capacity rating, but test data only goes to 65% loaded. The overall ISO efficiency in this case is ~62% @ 20u, which is the 50% loaded point.