...I mixed 1 quart of M1 5w-20 in with 3.5 quarts of GC? Would that do anything as far as thinning it down ever so slightly? I have a 4.5 quart sump, hence the oddball numbers there. Ain't 5w-20's in general chok full o' good stuff to help compensate for it's viscosity (or lack thereof)? I'm wondering because when my GC stash starts to dwindle down I'm eventually going to need something to mix in there...why not try to thin it up a bit??