My engine swap in a Case CX47 mini hoe...Took out a well used Yanmar and swapped in a 1903 Kubota..My top issue is the fan , I think.. I had to replace the engine fan with an electric fan.. [ Mr Gasket # 1987 ]. Supposedly the Gasket fan is good for 1800 plus CFM.... The Kubota waterpump is slightly off center with the crankshaft , so the blades would have to be trimmed to fit.. This is why I opted for the electric fan..Swapped out the thermostat..Turned the fan blade assembly around and made sure the fan rotation was correct.. It'll blow yer hat off..The radiator was taken out of the same machine the engine came from..It was clean as a whistle.. I took the waterpump off again to make sure no rags were left in there [ to keep mice out while apart].. Made the fan continuous run with key on..Took thermostat out and tried it..I'm kinda wondering if there isn't enough air supply for the fan to pick up.. Most of the body surround panels are gasketed and tight..I think I'll take off a side panel to try anything different.