In contrast to the oil cooling system, the water cooling system of the G-60 is adequate for any use. I drain the antifreeze out each spring, and install pure water with Redline Water Wetter. This increases the cooling capacity of the system and maintains corrosion protection (antifreeze just doesn't cool as effectively as plain water). A 180 degree thermostat, and low temp fan switch should be standard equipment (particularly the fan switch).
Pressure test your system. You'll be amazed at the leaks that spring up at 15 PSI. Although antifreeze raises the boiling point, we've never had boiling without it. It just never gets that hot, and even plain water (with a 15 lb cap and a system that holds 15 lb of pressure) won't boil till around 250 degrees.