Due to what I would consider to be misinformation , go to thedieselstop.com , these are the guys with the most experience on this matter . The IDI engines are generally considered to be far more reliable than their electronic counterparts . I say check the coolant for additive , (you can buy test strips) , if it has it and appears to have been maintained , go for it . Anything that hasn't been maintained can be ruined rather quickly . Early cummins are great engines , unfortunately the truck around them really didn't come around until a few years ago (arguably, but , all the auto's are weak).