[DEWFPO]

For clarity: Rarely does an oil filter's bypass valve kick in. Only when a filter is getting plugged up or the oil is so thick (from cold/viscosity) that the differential pressure across the oil filter element exceeds a predetermined value (which varies depending on the engine application), the bypass valve opens so oil can continue to flow to the engine. A portion of the oil still flows thru the filter if it can. An oil filter is rarely ever completely plugged, unless it has never been changed or there is a problem with the engine.

As well, if the engine is operating fine and the bypass kicks in because you are running straight 30 weight dino in -30F temps, as soon as the oil thins out the bypass stops and you are filtering ALL of your oil again. That's the same oil that was sitting in your oil pan, clean, filtered oil. So it's not a problem to run that oil thru your engine for a few minutes under the unlikely conditions I mentioned above.

There is NOT a bunch of junk floating around in your oil. Only small enough particles that are not filtered out by your filter (bypass or not). That's what makes it dark. The only way to remove those is to run something like an Amsoil dual/bypass filter that filter's down to sub-micron levels.

I hope this helps.

DEWPFO