2008 Outlook just 100,000 miles, has been using coolant for a long time, not a lot, cooling system holds pressure for a long time.
I read a note on the Saturn water pumps where running the coolant low can reduce the lubrication to the water pump seal, leading to leaks.
I notice that the cooling system on these vehicles has an enormous reserve capacity, where you can run the vehicle with practically no coolant and it still won't show a temperature rise, then when you lose that last cup, the temperature rockets to the top.
I read a note on the Saturn water pumps where running the coolant low can reduce the lubrication to the water pump seal, leading to leaks.
I notice that the cooling system on these vehicles has an enormous reserve capacity, where you can run the vehicle with practically no coolant and it still won't show a temperature rise, then when you lose that last cup, the temperature rockets to the top.