I need to find instructions for oil and filter change- air conditioning filter change and a on line source for discounted parts for 2000 MB E320. The factory service intervals are spaced too far apart and I am going to do it my self. I am not shure they are changing the oil when I bring the car to them, the oil is very black and the engine has a slight valve tap when first started. Should this car be using syntechtic oil? What kind of oil should I use?