OK I'm gonna fess up now...this is a dumb question but I've got a lot of dumb questions floating around in my head. At any given time how much oil is actually circulating in the engine? For instance, my Explorer holds 5 qts but that amount isn't doing "oil duty" if you know what I mean. Is it a qt, half a qt or 2 qts? Anyone know? Anyone want to venture a guess? Anyone care?