Oil is now black at oil changes. Doesn't smell burt or look gritty just black. I have been using fhram ultra filters and my oil was always a dark brown after 6000 miles but never black. Have 3 vehicles i tried theses k&n filters on and all now have black oil. Not sure if its the filter or the oil but the filter is the only thing i changed in my setup thinking i was improving things. I will not buy again going to try napa platinum filters next