Cooling System Issues:
* Low Coolant Level: This is the simplest and most common cause. Check your coolant reservoir. If it's low, you need to find the leak and refill it (using the correct 50/50 mix of coolant and distilled water). A low level can be caused by a leak somewhere in the system.
* Leaks: Look for leaks around the radiator, hoses, water pump, thermostat housing, and heater core. A pressure test of the cooling system is often needed to pinpoint leaks that aren't easily visible.
* Radiator Issues: A clogged radiator (from internal corrosion or debris) will prevent efficient heat transfer. A damaged radiator (e.g., cracked fins, holes) will also cause overheating.
* Water Pump Failure: The water pump circulates coolant through the engine. A failing pump won't circulate coolant effectively, leading to overheating. You might hear unusual noises from the water pump if it's failing.
* Thermostat Problems: A stuck closed thermostat prevents coolant from circulating until it reaches its opening temperature, leading to overheating. A stuck open thermostat will prevent the engine from reaching optimal operating temperature, which isn't directly overheating but can still cause problems.
* Hoses: Cracked, pinched, or collapsed hoses will restrict coolant flow.
* Cooling Fan Issues: The cooling fan helps dissipate heat, especially at low speeds. A non-functional fan, a fan clutch that isn't engaging, or a faulty fan control module will cause overheating.
* Radiator Cap: A faulty radiator cap won't maintain proper system pressure, leading to inefficient cooling.
Other Potential Causes (less common):
* Head Gasket Failure: A blown head gasket allows coolant to leak into the engine cylinders or oil, causing overheating and potentially white smoke from the exhaust. This is a serious issue requiring significant repair.
* Warped Cylinder Head: A warped cylinder head can prevent proper sealing and lead to overheating and coolant loss.
* Clogged Heater Core: While less likely to cause a sudden overheat, a severely clogged heater core can restrict coolant flow and contribute to overheating, especially when the heater is on.
* Engine Issues: Problems like low oil pressure (leading to overheating) or a severely clogged engine cooling passages are less frequent but possible.
What to do:
1. Check the coolant level: This is the first and easiest step.
2. Inspect the system visually: Look for obvious leaks, damaged hoses, or other problems.
3. Don't drive the car if it's overheating: Continuing to drive an overheating car can cause severe engine damage.
4. Get professional help: Take your Alero to a qualified mechanic for diagnosis and repair. They have the tools and expertise to pinpoint the problem and fix it safely.
Overheating can lead to serious and expensive engine damage, so it's crucial to address the problem promptly.
