Unless you have a really BIG radiator, of which most buses do not, I would suggest you not run both engines with one radiator. On a big rig truck, this isn't much of an issue, but with a bus, most buses have marginal cooling to start with, let alone adding another 15hp engine to the strain. Plus-like what has happened to us, if you have a problem with the main engine, you still have the generator's radiator to run the generator while you fix the big engine-nothing like having air conditioning running on a hot day to take a break in the nice, cool insides. Good Luck, TomC