I recently changed my timing belt and all my drive belts along with gaskets and seals, waterpump dist. cap..spark plugs and wires..so the whole bang...i also flusha nd filled coolant...i was also due for my oil which i always change at 3000 but i noticed that it was darka dn dirty..i can't even see through the oil when i was filling a bottle with the used oil. why is it so dirty? should i change every 2500 miles a couple of times till it gets cleaned up? or is there an engine oil treatment i can use? appreciate any help