how many quarts does the cooling system hold
Your car might have an coolant reservior for expansion and where to add coolant vs a cap on the radiator as older cars did. If you just want to freshen up the coolant without flushing then try this. Most cars have a drain valve at the bottom of the radiator. Open the valve up without removing it and put a clean container underneath with the engine cold. You can add the correct coolant as a 50/50 mix of coolant and distilled water to fill the system up. I usually purchase a one gallon container of coolant and one gallon of distilled water. Mix a 1/2 gallon of each in a separate clean container and add till full. You'll probably have some left over.