I'm not familiar with that specific product, but it's probably along the lines of a "water surfactant". REDLINE "Water Wetter" is a common water surfactant. If you're not familiar with that terminology, do a little research using those keywords.
FWIW, 210 degrees is not uncommon in summer traffic. Your secondary fan doesn't even come on until 226 degrees if I remember correctly. The LSx motors are engineered to run at higher temperatures. These are not the sbc that Grampa drove.