losing coolant from the overflow bottle on a 2011 f150

If you are building up air in the radiator, your truck could have a bad head gasket or crack in the head.

So do a simple check first. Like an old fashion radiator cap, the cap on the plastic refill container needs to be turned until an audible click is heard. Pressure needs to build up in the system to increase the boiling point of the coolant. Since the truck is so new, the idea of a blown headgasket or defective thermostat or fan clutch seems to be remote, although possible.