* Faulty Cooling Fan: This is the most common cause. The fan is crucial for drawing heat away from the radiator when the car is stationary. The fan might be:
* Not receiving power: Check the fan's fuse and relay. A malfunctioning temperature sensor could also prevent the fan from activating.
* Mechanically seized: The fan motor itself might be broken or jammed.
* Bad fan control module (if applicable): Some vehicles have a dedicated control module for the cooling fan.
* Low Coolant Level: Insufficient coolant means less fluid to absorb and transfer heat, leading to overheating. Check the coolant level in the reservoir tank; if low, you need to add coolant (make sure the engine is cool before doing this). A leak somewhere in the system (radiator, hoses, water pump) is also a possibility.
* Clogged Radiator: A dirty or clogged radiator restricts airflow, preventing efficient heat dissipation. The radiator fins can become clogged with debris, insects, or even corrosion.
* Faulty Thermostat: A stuck-closed thermostat prevents coolant from circulating properly, trapping heat in the engine.
* Water Pump Failure: The water pump circulates coolant through the engine. A failing water pump will reduce or stop the coolant flow, causing overheating. You might hear unusual noises from the pump if it's failing.
* Head Gasket Failure: In a worst-case scenario, a blown head gasket allows combustion gases to enter the cooling system, pressurizing it and causing overheating. This often manifests as white smoke from the exhaust, milky oil, and/or loss of coolant.
Troubleshooting Steps:
1. Check the coolant level: This is the easiest and safest thing to do first.
2. Check the cooling fan: Try turning on the air conditioning. The AC should force the fan to run. If it doesn't, suspect a fan motor, relay, fuse, or sensor issue.
3. Inspect the radiator: Check for any obvious clogs or damage.
4. Listen for unusual noises: A whining water pump is a classic symptom of failure.
5. Check the thermostat (if accessible): You might need to consult a repair manual for your specific model.
If you're not comfortable working on your car yourself, take it to a mechanic for diagnosis and repair. Driving with an overheating engine can cause serious damage. Addressing the problem promptly is crucial.
