I'm going to be changing the oil again for the 3rd time in about 1000 miles...because the inside of my engine is DIRTY. Right now I'm only using cheap dino oil because I'm changing it so often and a good bit of it ends up on the road from my rear main leak. After I drain out all this dirty oil, might it be a good idea to pour a quart of clean oil in and drain it out again? Or maybe ATF, since it is thinner? Or is that just a waste of my time?