Cooling System Issues:
* Low Coolant Level: The most obvious. Check the coolant reservoir. Low coolant can be due to a leak (see below).
* Coolant Leaks: Look for leaks around the radiator, hoses, water pump, thermostat housing, and heater core. Pressure testing the cooling system is crucial to find small leaks.
* Radiator Problems: A clogged radiator (from debris or internal blockage), damaged fins, or a failing radiator cap can all restrict coolant flow.
* Water Pump Failure: A failing water pump won't circulate coolant effectively. Listen for unusual noises (whining or grinding) from the pump area.
* Thermostat Issues: A stuck closed thermostat will prevent coolant from circulating properly. A stuck open thermostat might *seem* to be working but will struggle to reach operating temperature, leading to less efficient engine operation which can *indirectly* cause overheating.
* Clogged Heater Core: While less common, a severely clogged heater core can restrict coolant flow.
* Fan Clutch Problems: The fan clutch engages to increase cooling airflow when the engine is hot. A malfunctioning clutch (either not engaging or engaging too late/weakly) will reduce cooling. Listen to see if the fan is running consistently at speed when the engine is hot.
* Faulty Radiator Fan Motor: The electric cooling fan might not be turning on or not working at full speed.
Engine Issues (less common, but contributing factors):
* Head Gasket Failure: A blown head gasket allows coolant to mix with oil or enter the combustion chambers, resulting in overheating and other symptoms (white exhaust smoke, milky oil). This is a serious problem.
* Cracked Engine Block or Cylinder Head: Less common but possible, especially if the engine has overheated severely in the past. This usually involves a significant coolant leak.
* Low Oil Level: Low oil can lead to excessive engine heat build-up.
* Timing Issues: Though less directly related, severe timing issues can cause inefficient combustion, leading to increased engine temperatures.
Other Potential Causes:
* Incorrect Coolant Mixture: Using the wrong coolant type or ratio (e.g., too much water) can impact cooling efficiency.
* Blocked Airflow: Dirt, debris, or a damaged shroud obstructing airflow to the radiator.
Troubleshooting Steps:
1. Check the coolant level: Add coolant if low (using the correct 50/50 mix of coolant and distilled water). Be cautious as the system is under pressure when hot.
2. Inspect visually for leaks: Look carefully around all components of the cooling system.
3. Feel the upper and lower radiator hoses: When the engine is running, they should both be relatively warm. A significant temperature difference suggests a problem with coolant flow.
4. Check the radiator fan: Make sure it turns on when the engine is hot.
5. Listen for unusual noises: Pay attention to noises coming from the water pump area.
If you're not comfortable working on your vehicle yourself, take it to a qualified mechanic for diagnosis and repair. Overheating can cause serious and expensive engine damage if not addressed promptly.
