Some of the oils that were mentioned here are not certified for diesel engines. The 15W40 Delo 400 Multigrade is one of the best oils for diesel use. The Delo is what is termed a "universal" grade oil. Whatever you use, see that it has a secification such as CE, CF, or CJ, for compression ignited engines. Virtually all oils have an S certification for spark ignited engines. My original 240D engine went 380,000 miles on Delo 15W40 multigrade, so it can't be too inferior. The universal grade oils have additional cleaning agents to disperse the soot present as a combustion byproduct in diesel engines. The universal grade oil is really no more expensive than any quality dino oil.
There are plenty of good oil brands out there, with Castrol certainly being one of them, but ENSURE that the can or jug you pick up has a "C" specification.
Also for northern climates, 15W40 would be better than 20WXX. The 15 will handle colder temperatures than 20. 15W40 is what I use year round in Texas, so it will certainly handle the summer season.
As far as anti-freeze goes, I use whatever decent ethylene-glycol I can get and change it frequently.
As far as using "heavy duty" stuff not being worth the extra cost, if it's worth driving and maintaining, it's worth the best. And in the case of oil and antifreeze, the good stuff only costs a little more.
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
[This message has been edited by LarryBible (edited 08-17-2000).]