Does a bad heater core make cars overheat?

A bad heater core can contribute to a car overheating, but it is usually not the sole cause. A heater core is a small radiator-like device that uses the engine's heat to warm the air that flows through the car's ventilation system. If the heater core is clogged or damaged, it can restrict the flow of coolant through the engine, which can cause the engine to overheat. However, there are other more common causes of overheating, such as a faulty thermostat, a damaged water pump, or a clogged radiator. If your car is overheating, it is important to have it diagnosed by a qualified mechanic to determine the exact cause and get the right repair.