I love my 71 220D............. It has ben great... Here are the problems I have had..... GLOW PLUGS!!!!!! That is it..... they burn out quickly....... I have decieded to upgrade mine to a new system all together........... I met another guy that did that and his problem went away!!!!! Other that that I am happy with my half a million miled car........ Yes.. SLOW it will be, but reliable......... Just watch if you get into the negative temps...... starting is a pain if you don't plug in...... So what to look for.. well rust(which I am sure you knew) Trunk seals...... diesel will get into the trunk, My gas guage needed replaced about 7 years ago...... works now, my horns went out....... That's really it............. It has been a suburb car.......... I love mine!!!! Oh yeah... Subframe bushings........ I did those when I first bought my benz in 97..er...98???