New to Diesels

[yankee8]

Hi. I bought my first diesel, a 1976 300D, to keep my '85 500 SEL company. I've never had a diesel before and am waiting to receive an owner's manual. I did a search and saw a lot of discussion about motor oils. I'm still confused as to what is the recommended viscosity. I live near Tijuana where it rarely gets very hot or very cold. Also, I don't understand what kind of maintenance is required for the injection pump. Is that for fuel or oil? Anything else a novice diesel owner should know?
Thanks in advance for your help and thanks to everyone for putting up this board.
Paul