Ahh! That is how they get rid of their sludge! From some of the ships that come over here I always thought they emptied the bilges in the BAYS!!!If nothing else pull the dipstick and check inside for metal, before you buy. I service equiment that sources their parts from Dayton. Apparently just a couple of years agao they were USA built, new ones are now all china made. When you pull the dipstick and run your finger inside, it comes out bright metallic grey from the metal sludge left from the factory.