For those who think oil filters don't do anything

[Winston]

Here are some particle counts of used oil with various filters and a particle count of virgin Valvoline. Seems like even new oil benefits from being filtered in your oil filter.

Used oil

Used oil Particle counts

New oil

Virgin Valvoline

 

[Shannow]

Molakule has stated previously that some of the particles that are seen VOA are additives (calcium compounds).

At work, we filter hydraulic fluids into sytems with clearances in tenths. But hydraulics don't have many additives, and even then, they start out at ISO 18 or thereabouts.