For what it's worth (and not tractor-specific): I prefer to drain the old coolant by removing the lower radiator hose at the radiator. Then I reconnect it and flush by refilling with plain water, runing it up to operating temp, and draining again. Then I add the calculated amount of concentrated coolant based on the spec. volume of the system and the desired concentration (I always try for 50-50). Too strong a glycol concentration can cause an insulating film inside the engine. Last, I top up with plain water and check with a hydrometer. I think clean tap water is fine for cooling systems unless it is very acidic. Almost all coolant is mainly ethylene glycol however some is propylene glycol, which is less toxic. Ethylene glycol is toxic to all animals with hemoglobin blood. BUT the various formulations include different additive packages (e.g. water pump lubricants, anti-corrosion additives, wetting agents, etc.) which can be quite important in some applications. It is the additives that "wear out." I can't find any specific coolant recommendation in Kioti owners or service manuals don't but I suspect the stuff labeled for Asian cars would be fine.
