minimax

Steve: this supised (sic) know all knows better, that's all.

There is just as little pressure exerted in the cooling system if the liquid is not boiling. If boiling point were the criterion, we would cool the engine with oil (as of course we do). The cooling system is pressurised to prevent it from boiling so you don't need anything other than what has been in use since before you were born.

Far better to have a coolant warning device to warn of a pressure cap failure as a pressure cap failure is likely to affect coolant circulation rather than use a coolant that may mask a fault.

Waterless coolants are used in aero engines because the boiling point reduces with height above sea level and the pressure differential is correspondingly greater than for a land based vehicle. I reiterate that you don't need it in a K series engine whatever any well respected motor club might assert and if that upsets you, that's just tough.

Properly operated and maintained ones don't go wrong and to assert that they will be improved by an expensive coolant is twaddle, fiction and bosh! The evidence is in the tens of millions of cars that have gone from manufacture through a long service life to scrapyard without ever needing it, as they do to this day.