Mashman

I've never flushed a coolant system before, and have a question.

After I flush the system, I will have plain water in the engine block and heater hoses. After I drain the radiator, do I simply fill the radiator with non-diluted ethylene glycol coolant? Is the radiator around 50% of the capacity of the coolant system? Or is the radiator a larger percentage of the system, and therefore I would want to dilute it?

MelWff

when you drain the radiator from the bottom petcock you are draining most of the fluid out of the whole engine. You need about 2 gallons of straight antifeeze and 2 gallons of distilled water or 4 gallons of the pre-mixed antifreeze.

7T1vette

Flush it; drain it; add 2 gallons of ethylene glycol antifreeze (100%); then top off with whatever distilled water you need. Leave radiator cap OFF, as you warm up the car. Allow thermostat to open (note coolant flowing in radiator) and trapped air to be expelled; then add water until level doesn't change. Re-install cap.

If you have an overflow system, just keep fluid in the O/F tank at the required level.