Just as we we were making some progress with cleaning and painting, we had discovered it had a leak. We were able to narrow it down to the radiator, and after hours of searching every hose fitting alas, we could not locate the leak and had given up, we called the international dealership, we called diesel mechanics and to look at the bus alone was $900! (Not counting parts or cost to repair). Luckily after talking to a few of our co-workers they had given us a great tip and had made all the difference. As suggested we took the radiator out ourselves and sent to the radiator repair store. 

There are main hoses for the inlet and outlet of the radiator, and if you have a 1999 international you will also have two transmission lines, the fluid is transmission fluid, do not be alarmed! Recommend removing the hood before you attempt to remove the radiator it will be so much easier. Buy 1/2 inch plugs (the type that go on test tubs), to cover the transmission lines and wrap it up with tape. Drain the coolant from the radiator and cover the inlet to not get dirt inside the hoses when the radiator is out for repair. 

There are two parts to the radiator the first part is the big side, which was completely shot for us. We took it to a radiator repair man (should be able to find one in your local area) and luckily this is is a common part that they had on shelf they could sell us, (thank goodness, we had no idea what part to order!). They charged us $600 and after looking on line and talking to the other places this sounded like the best deal. Replacing the radiator was pretty straight forward after this.