If you want to drain and refill your radiator, its around 3/4 gallon. If you remove the bleeder screw and drain the engine block as well...total would be about gallon and a half. Make sure you turn your heater on, engine at normal operating temperature( so that thermostat can open), and loosen the bleed screw above your thermostat housing. This would let air escape, then you can add more coolant until heater core, engine block and radiator is full. Don't forget to fill the reservoir. This is the "reserved" portion that gets sucked back into the cooling system when engine cools down. Just buy 1 gallon of Toyota "RED" antifreeze and mix with 50% water for a 50/50 mix. This would be a total of 2 gallons...enough for your coolant change.
