I don't see any problem with using a very small amount of coolant, I just wouldn't add very much. Between a little coolant and Red Line water wetter, it will help prevent algae from forming in the cooling bucket as well as limit corrosion of the aluminum parts. ( for those who don't change the water each time)
As a side note, I started out using the full synthetic Husky compressor oil in my YH when it was new, but after experiencing detonation and a broken 2nd stage piston, I moved to a better oil. Yall do as you like, no Royal Purple or Huskey for me, and I no longer get the crackling sound I used to get when I used the Huskey. YMMV.
