Gmat - the comment was related to how to use pure distilled water without getting bacterial growth
Redline WW, alcohol, and others lower the 4 of the physical properties of the fluid, altering the cooling abilities of the system (the properties altered are density, viscosity, specific heat, and thermal diffusivity). Admittedly the amount varies with the ratio and
can be quite small, but if you are looking for every last little bit...