It’s great that the Evans coolant has a boiling point far above that of traditional water-based coolants. In situations where normal coolants boil so much that not just steam bubbles but whole steam pockets form, the Evans coolant may prevent localized hot spots. Being non-corrosive is a further plus.
Not so good is that the viscosity of Evans coolant is about three times as high as traditional water-based coolants. More horsepower will be required to spin the water pump.
Evans doesn’t state what the heat transfer coefficient of its coolant is – how much heat it absorbs as it flows through the coolant passages. Water flowing through coolant passages absorbs more heat than air would. If Evans doesn’t absorb quite as much heat as water-based coolants, it will cause the engine and the engine oil to run hotter overall. A report prepared in 2012 which Evans has on its website indicates that may be the case:
http://www.evanscooling.com/assets/Uploads/EvansFinal-Report05022012Deliverable.pdf. The engine oil temperature increased by 2.0 - 4.3% with no changes other than swapping out the water-based coolant for Evans. A hotter-running engine can reduce emissions but it will also thin out your engine oil a bit.
Our water pumps, coolant hose diameters, thermostats, cooling fan switches, etc. were designed for a coolant with the viscosity, heat transfer coefficient, and specific heat capacity of a water-based coolant. If Evans changed nothing but the boiling point and corrosion properties it would be fantastic. It would have nothing but upsides. Unfortunately, since the Evans coolant is thicker and doesn’t seem to transfer heat quite as well, there are also some downsides.
