Pulled the heads off my 01 today. Suprised to see how clean the thing is inside. Truck has almost 320000 miles on it and a tire shop owned it before me. The oil seems to stay clean a lot longer then my lmm. On my last 03 lb7 the oil would still be nice and clean at 3000 miles when id change it. After working on so many powerstrokes this really suprises me.