Well, I've gotten to a point now, where there will people who will be disappointed if I don't jump in with my oil change lecture.
Whatever the manual says for oil change interval, cut it in half and change the filter every time. Oil changing is the cheapest engine insurance money can buy. Regardless of the brand of oil you use, changing it is the ONLY way you have to clean the inside of the engine.
Even more importantly, you have one of the many MB engines which require particular attention be paid to the timing chain system. Frequent oil and filter changes prevent the microscopic particulate matter from eating the chains and associated important parts.
Be fanatic about oil changes and timing chain maintenance and attention, and you will enjoy your new hot rod for a long time.
Change oil hot and change oil often,
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in