* Coolant Leaks: This is the most frequent cause. Check for leaks around the radiator, hoses, water pump, thermostat housing, and engine block. Look for puddles under the car, especially after it's been running. A slow leak might only be visible as a dampness or staining.
* Faulty Thermostat: A stuck closed thermostat prevents coolant from circulating, leading to overheating. A stuck open thermostat can also cause problems, though it's less likely to result in immediate overheating; more a symptom of consistently low temperature.
* Radiator Problems: A clogged radiator (internal blockage from sediment or external blockage from debris) restricts coolant flow. A damaged radiator (leaks, fins bent or broken) also reduces its efficiency.
* Water Pump Failure: The water pump circulates the coolant. If it fails, coolant won't flow properly. You might hear unusual noises from the pump if it's failing.
* Low Coolant Level: Simply having insufficient coolant in the system will cause overheating. Check the coolant level in the overflow reservoir (when the engine is cold).
* Faulty Fan Clutch or Electric Cooling Fan: The cooling fan(s) draw air across the radiator to dissipate heat. If the fan isn't working properly (either not engaging or not spinning fast enough), the engine will overheat. Listen for the fan to activate when the engine is hot.
* Head Gasket Failure: A blown head gasket allows coolant to mix with engine oil or enter the combustion chamber. This is a serious problem and requires immediate attention. Check your engine oil for a milky or brown appearance (indicative of coolant contamination). Also, check for white smoke from the exhaust.
* Clogged Radiator Cap: A faulty radiator cap prevents proper pressure buildup in the cooling system, hindering efficient cooling.
* Problems with the Cooling System Pressure: A leak in the system can cause a loss of pressure, affecting the boiling point of the coolant.
What to do:
1. Do NOT attempt to open the radiator cap while the engine is hot! The pressurized coolant can cause severe burns.
2. Pull over immediately if the temperature gauge indicates overheating. Continuing to drive can cause severe engine damage.
3. Let the engine cool completely before attempting any inspections.
4. Check the coolant level.
5. Visually inspect the hoses, radiator, and water pump for leaks.
6. If you're not comfortable performing these checks yourself, take your Cadillac to a qualified mechanic. This is crucial for accurate diagnosis and safe repair. Ignoring overheating can lead to catastrophic engine failure.
