John Deere 6x4 coolant leak

[John H.]

I have a 2001 JD 6x4 gator with a mysterious coolant leak. Every few days I have to add coolant to the bleed port in the engine. Everything is fine for a day or two, and then I have another overheating problem with the radiator fan not coming on. I can’t find any sign of a water leak. I have replaced the radiator cap, and I guess the next step is to replace the water pump. Any other thoughts as to what could be the issue? The Kawasaki engine has 3200 hours, and the oil is clear, so I don’t think the engine itself is the issue.