Q: Coolant leak.

The cooling system needs to be checked for leaks. Look for areas where there is a white buildup from coolant spray that has evaporated. A pressure test of the cooling system needs to be performed to see where the leak is originating and then the leak needs to be inspected. Common leaks can be located at the cooling system hoses, heater core, radiator, thermostat housings, and also at the water pump. If a white buildup from the leak source is not noticeable, then a pressure check or penetrating dye may be the only options for locating the leak source. You may want to enlist the help of a mechanic, like one from YourMechanic, who has the equipment necessary to diagnose and the repair the coolant leak.