Just a point of information on filtration removing oil additives. Most oil additives including ZDDP (the zinc and some of the phosphate you see in oil analyses) are way too small to be removed by filtration. However, as they do their jobs by binding to wear particles and soot, the filter will eventually remove the bound additives as the particles are removed. That's where the additives "go" as they decrease during repeated oil analysis of the same oil. But one limitation of spectronic oil analysis is that it does not discriminate between free and bound additive remaining in the oil. As small "harmless" wear particle accumulate with use, they bind certain anti wear and dispersant additives and prevent them from doing their job at bering and ring surfaces. That is one of the reasons why oil is condemned when wear metals reach a certain level even though analysis still might still show plenty of ZDDP, etc. It is controversial whether or not colloidal anti-friction additives such as moly disulfide can aggregate and be removed by filtration during extended drain intervals.
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1999 Quad cab 2500, SB, SLT, 4X4, 5-speed, 3. 54, tow and camper package, Lance 820 camper, Lance cabover stabilizers, Rancho 9000s, Airlift airbags