As someone with a vested interest in aluminium radiators (over a hundred manufactured and sold already this year) in a plus 8 use a 50/50 mix of blue glycol antifreeze and water. It’s what the engine was designed to run
I was running my new SiFab radiator with precisely this coolant mixture in mid-thirties temperatures in Italy this summer and the temperature gauge steadfastly refused to budge above normal.
