My 2 cents.

Fuel filters, main and in line. Look for algae evidence. ( black colored fuel)
Fuel lines, look for leaks/cracks/damage and replace
Valve adjustment. Check timing chain stretch while there.
Diesel purge/ injector cleaner ( Techron).
Oil/filter change.
Air filter change, if necessary. (check air filter mounts)
Replace the following filters, Power steering. (change the fluid initially to the same fluid. Going from ATF to power steering fluid ( or vis a versa) may produce leaks in the system). SLS suspension filter in the reservoir tank (TD only).
Tranny fluid/filter change.
Check Air Conditioner charge.
Check charging system.
Vacuum line connectors and condition. Replace connectors if old/cracked.
Antifreeze, Change to Mercedes.
Engine/ Tranny mounts and shocks. Check condition.
Check front and rear suspension condition.
Entire vacuum system check. Engine/door locks/Air Conditioning system
Wash and wax the girl.
Enjoy

Dave

__________________
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