I think it's time to drain & replace coolant in my 2 year old 460 and I am unsure as to what to use. Appears to now have mixture of anti-freeze & water. I live in Northern Ohio where it can get cold, but do not normally take out of the heated garage in freezing temps. Engine is steel block, aluminium heads, 500 hp, 10&1/2 to 1 compression. Should I use something like Prestone Heavy Duty Flush before final concoction? What should final concoction be? Also, I've heard an old wives tale that something needs to be added to prevent electrolysis between the metal & aluminum-not true is it?