skankyfrankie

Here is how I always change coolant. Drain it from the radiator, refill with distilled water, run until warm, let cool then drain again. Refill and run until warm, let cool then drain again. Usually repeat this 3-4 times or until drained fluid is looking pretty clear, may have a little color but mostly water. Then on the last fill I add exactly 50% of the specified volume of full strength coolant. Then I top off the rest with the distilled water. This gives you almost total replacement and correct 50/50 mix. Anything else besides a power flush or pulling the block drain plugs is just 1/2 a change IMO. Takes 8-12 gallons of distilled water and around 4 hours, mostly waiting time for cool down, I run a big fan on the radiator to speed up the cool down. Never add cold water to a hot engine.