The OEM rear filter / water separator is rated at 4 micron absolute. That “CAT” filter you’re referencing is not a true “CAT” and is made by Baldwin. It’s a BF-1268 painted yellow with a CAT logo on it. It’s a 13 micron absolute filter, 4 micron nominal. Since it has a “nominal” rating, that means its efficiency is below 98.6% and doesn’t in fact capture everything in the 4 micron range.
I spoke to Cat about that particular filter, as well as the 396-4596 oil filter that will fit our trucks. Both are not CAT products and they cannot supply the specs on them as they don’t manufacture them. I therefore spoke with Baldwin who makes both of those filters, as well as the OEM filter for our trucks. At the recommendation of Baldwin, they suggested to stay with the OEM filter as it provides better filtration than the faux CAT filter that comes with the aftermarket adapter.
This is Baldwin’s reply to my request for information regarding the OEM fuel filter / separator and their over the counter equivalent BF46152:
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