I have 1989 Bobcat 743 I recently changed the water pump on it. I also checked the thermostat, there is also no obstructions on the radiator. I drained the oil and their is not any antifreeze in the oil. The engine in it I beleive is a v1702 Kubota. With the radiator cap off you can see the antifreeze flowing through the radiator. You can run it at full trottle just sitting their and it won't over heat but, after 10 minutes of running it it will overheat.