I am in the middle of doing a cooling system flush and each time I remove the bottom radiator hose to drain it off, I get about a gallon of coolant/water out. Since the system holds just over 12 quarts, that's about 1/3 of the whole system coolant. What is the capacity of the overflow bottle? I want a 50/50 mix when I refill and just topping off with pure anti-freeze won't get me that if I'm only draining off a gallon at a time.
If I drain the radiator and start the car, the t-stat is still closed, so I doubt it will refill with what is left in the block. Is there a drain plug on the block that is easily accessible or is there a better way to do this?
