[Sirrotica]

Was watching you tube videos by, Rainman Ray, yesterday, he's a line technician that video tapes his everyday repairs on You Tube.

Says he never fills an oil filter, and when he shows that in his videos , he immediately gets all kinds of flak in the comments section. He states that CAT specifically recommends that techs DO NOT PREFILL filters on hydraulic, or engine oil systems for this reason.

You fill the clean side of the filter through the center hole, if there is foreign substances in the oil bottle, the bulk fill nozzle, funnel, bulk container, etc. you introduce the substance directly into the portion of the system that is supposed to have filtered oil only, bearings in an engine, pump in a hydraulic system. That will immediately damage either component.

I totally agree with this reasoning, in the last 55 plus years of wrenching, I have never prefilled any filters, and I've changed a mountain of them.

He goes on to say that in a typical automotive shop, or in the case of construction equipment being serviced in the field, that it is nearly impossible to be certain you aren't introducing some minute substances that are invisible to the naked eye, I totally agree. The small dirt causes 3.6 times more wear than 20 micron, and larger particulate does. The reason for by pass filters.

Anyway that's CAT's reason, I believe it's a valid concern.

Last time this was brought up for discussion I thoroughly researched oil filter manufacturers directions for filter installing. Not one manufacturer ever encouraged prefilling filters before installing them, but none gave a reason for not doing it.