Regular green coolant will be perfectly fine.I use a 50/50 mix with distilled water.The pre-mixed coolant with de-ionized water would be even better and easier.Good Luck!
Any special coolant for diesel engines is for newer engines.The OP's B9200 is a parent bore(no cylinder liners)engine which would have come with ethylene gylcol coolant as the factory fill.Drain and refill every two years,using distilled water or de-ionized water to elimate any unwanted chemicals(lime here)is all that is needed.
A comment from fieldserviceengineer from the Oils,Fuels & Lubricants section would clear this up,but I am confident in my recommendations.Good Luck!