What year is the Onan Quiet Diesel? You may have one belt or two and if you have two, you will probably need to get the new fan kit that allows you to go to one serpentine belt. I had my belt changed at 2500 hrs and it looked new. Also had my brushes replaced and they were over 50% left. Hoses were also good and mine was a 2005 model year. It's your call but be prepared for all to be good. Changing the oil, fuel filter and air filter takes less than an hour. Look at 4+ hours to do the belt(s), hoses, brushes. Also, where did the "refrigerant" come into play as there is none that I know of in a generator?