Which oil and filters are a huge debate. My recommendations

Mercedes filters only, Join the Mercedes Benz Club of America so you can get a discount on parts and service at the dealer. Some times whole sale prices.

Oil, I also use Rotella, Its designed for diesels and cheap at Walmart. Change your oil and filter every 3000 miles if you want the engine to last.

Change all the fluids in the car, Oil, antifreeze, power steering fluid and filter, tranny filter and fluid, Change all filters, air fuel ( inline and main fuel filter) Make sure you have inline vacuum filters.

Check all vacuum lines and 2way, 3way and 4 way connectors. inspect all hoses for condition. Change drive belts if they look old and cracked. Check brake pad wear.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car