Hey guys In need of some assistants. So my mustang is away for the winter and the car hasn’t been started in over a month. Came home from work the other day to find a big pool
Of coolant under the car. Upon farther investigating I saw the leak was coming from the Y connector to the thermostat (shown in pic). I’m sure it’s a bad O ring in there but to replace it will I need to empty all the coolant then fill it back up after the repair is done or is there a way to get around having to empty...

2011 mustang GT coolant leak