Is the valve adjustment really going to make things better? I know that 203k mileage is not that much for a diesel engine, but still, its age could prove to be a problem. Even with small overall mileage, motors tend to alter in time, and the one you mentioned is almost twenty years old. I would definitely buy it for the right price, given that you have room for other repair works should they be needed. Also, it would be best if you considered buying from a
car wreckers yard. Other defects could appear in time.