I want to interject something here. The oil filter bypasses,circulates unfiltered oil,via a bypass when there is too much restriction in the filter. Things that would at least in theory contribute to this bypass,would be a finer micron filter,too thick of oil,too high pressure oil pump,and of course a plugged filter. Now when we start playing with things we need to take this into consideration. Let's say I've got a high volume pump,running 60psi oil pressure,got a fine micron filter,running thick oil,and never really make long drives getting things hot,not only to evaporate the moisture out of the oil but also never gets to proper viscosity. Now how much of the time is my oil not being filtered at all. Just through the screen through the pump,into the oil galleys. Just food for thought.