Our 2002 Toyota Sienna's cooling system capacity is 10 quarts (no heater). Using radiator petcock, 5.7 quarts of coolant is drained. Recommended mixture is 50/50 antifreeze and distilled water, which is what it is now before the replacement starts. Drain-1: Refill with distilled water only. Run engine till thermostat opens + 10 minutes. Drain-2: Refill with distilled water only. Run engine till thermostat opens + 10 minutes. Drain-3: Refill with 1 gallon of undiluted antifreeze and 1.7 qts of distilled water. What will the percentage of antifreeze end up being? Please show the step-by-step calculations so I can learn how to do it. Thanks.