What Causes My Car To Overheat? Quite a few things can cause your car to overheat. It can be as simple as the coolant being low. If you have a low coolant condition, there is usually a reason that it is low. It could be anything from a loose connection to a Head Gasket going bad that allows the engine to burn coolant. A pressure tester needs to be hooked to the cooling system when it’s cold and then the tool pressurizes the cooling system. This way if it is leaking you will be able to find it. If there is no external leak and you still wonder, Why Does My Car Overheat it could be the water pump may be going bad and not able to move coolant fast enough through the system. Also, the Radiator could be getting plugged or restricted enough that it won’t allow the coolant to flow through. If all these check out and are working as designed, it’s possible that the Head Gasket could be bad, and the Engine is Burning Coolant. A lot of times when this happens you may notice that your car smokes when it starts and then clears up. That can be an indication that the Head Gasket may need to be replaced.