I believe an engine runs cooler with anti freeze.
Do not put all anti freeze in the system, at least some kinds, without some water. Mix per instructions.
One container read ""PLEASE"" Do it our way first"
Also as pointed out on another list do not run an engine without a thermostat. Especially the later ones with alum. heads.
Years, years, years ago they did run cast iron engines without t-stats. Did it hurt them any??
At that time I believe b4 antifreeze, alcohol was used. It boiled at a lower temp.
In the early years of anti freeze Zerex would leak where Preston would not. So I'm told. Not sure where the leak would be but gaskets were not of the greatest quality.