This tractor is about 10y old? How many hrs and overall shape? Does it have cab?
If you have possibility, look for cabbed 62 or 7245, as they have bigger 4cyl engines, for your size of farm.
Seems that 3 bangers like to overheat. Don't know reason why.
Zetor is simple, durable, hardworking tractor. It has some little problems like leaks, brakes etc, but nothing serious.
If you'll find good one, don't hesitate to buy it.
BTW, ask Chipperman, he is Zetor dealer.