GMC Sierra 3500 HD Car overheats quickly Inspection at your home or office.

Common reasons for this to happen:

• Low Coolant: Perhaps the most common reason for your car to overheat quickly is low coolant in the engine. If there isn’t enough coolant, the engine’s temperature cannot be regulated correctly. Coolant can be lost for a number of reasons, ranging from boiling over (serious overheating) to leaks from aging hoses, gaskets and more.

• Failed Thermostat: Another very common reason for your car to overheat quickly is if the thermostat fails. The thermostat opens and closes based on engine operating temperature, allowing coolant to flow throughout the engine, or restricting it. If it sticks closed, your engine will overheat very quickly. Your car’s heater will also blow cold air.

• Failed Water Pump: While rare, water pumps do eventually fail. They’re usually replaced with the timing belt, so if you haven’t had this service yet, it might be the culprit. If the water pump fails, coolant will not circulate through the engine at all and it will overheat very quickly.

• Failed Radiator Fan Motor: If the motor on your radiator fan fails, it will cause your engine to heat quickly. Overheating isn’t always a problem here, particularly if the weather isn’t that warm, but it is a possibility.

• Failed Radiator Fan Relay: If the radiator fan relay fails, the fan will not cycle on and off, which eliminates some of the airflow over the radiator. This is particularly problematic during stop and go driving (highway driving generally provides enough airflow to cool the radiator without the need for the fan).