Well I didnt even have to finish my test to see what the "real" deal is. I pulled pint after pint into 16 oz.arrowhead drinking bottles & refilling with the same amount each time to keep from a overflow. & after 4, the oil was still the same, BLACK! Just like the crank case that needs a change.Then I decided to just keep filling the res & it NEVER over filled. It's more than obviouse that the system recurculates & does it pretty fast. Looking in the little filler hole, the oil was 1/4 or so from the top. Pour in another pint & it's still the same. The return rout is at the top of the res, & the "sump" pump is what's pushing it around, NOT the high pressure pump. This is what I came up with & don't understant how anyone can have black oil in that res after a oil change unless your return gally is blocked, or there's a mechanical part involved in alowing the return that goes bad. So now I know & I don't have to waste any time ever doing that again. Now the question is, do some motors have a oil return problem that lets the dirty oil stew up there? I know mine is fine.