Don't forget to examine the ratings on the oil you choose. There are S (spark ignited engines) and C (compression ignited engines). Ensure that the oil you select has a C rating for your diesel, such as CF, CG, CJ etc. SG, etc without a C rating have not been tested for use in diesel engines.
Change oil hot and change oil often,
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in