spent the day yesterday helping the kid get his new shop up and
running...

Ain't no way he'll have it it tight enough to heat 24X7 for a MN
winter this year. many years ago, I took old car radiator coolant to
use in my old shop - just added oil. Well, 30 years later I guess this
is bad form. Will RV antifreeze plus oil work OK in his CNC mill?
Other suggestions?

Karl