Q: What could be causing my 09 Ford Fusion to leak excessive antifreeze run hot and heat not to work

Hello. Thank you for writing in. The coolant leak is what is causing the engine to overheat. Without proper coolant flow, the engine is not able to transfer it heat away from itself. The hot coolant is also used in the heater core for use with the climate control. It is the lack of coolant that is causing the heater to malfunction. With that in mind, the engine can also be suffering other damages that will cost time and money down the line. If you are going to be driving the vehicle, carry coolant and always top off before driving or starting it. With that said, it is still not ok to drive the car excessively, and this is a repair that will want to be made as soon as possible. The coolant leak needs to be the focus of your attention. The vehicle most commonly leaks coolant from hoses, the water pump, freeze plugs, or physical engine damage. A visual inspection will likely show you the source of the coolant leak, then repair the damage.