Hi, I'm looking at a 1991 350SD W126 with 230K miles in total and 150K miles on engine and transmission. According to the owner the original engine/tranny had been replaced under warranty.

I don't know much about these diesels but I've read about early 6 cyl. OM603 engines not being very reliable. I want a daily driver that will take 20-25K miles a year under regular maintenance.

Someone told me that Mercedes solved the problems so late 603.97x are supposed to be solid. Any input? What should I be looking for?

Thanks!