Here's what you should do immediately:
* Pull over safely: Find a safe place to stop as soon as possible. Do not continue driving.
* Turn off the engine: Let the engine cool down before attempting anything else. Overheating can cause serious damage, and continuing to drive will worsen it.
* Check the coolant level: Once the engine is cool enough to touch safely (wait at least 30 minutes), carefully open the coolant reservoir (expansion tank). Check the coolant level. Be cautious; the coolant will be hot and may be under pressure. If the level is low, this is a likely cause. Do not open the radiator cap while the engine is hot!
* Inspect for leaks: Look for any visible leaks around the radiator, hoses, water pump, and engine block.
* Check for any obvious damage: Look for any damage to hoses or the radiator (e.g., cracks, bulges, or holes).
Possible causes (in order of likelihood):
* Low coolant level: This is the most common cause. You'll need to add coolant (the correct type for your car—check your owner's manual). However, simply adding coolant is a temporary fix; you must find and fix the leak.
* Leaking hose: A cracked or loose hose is a frequent culprit.
* Leaking radiator: A hole or crack in the radiator will cause coolant to leak.
* Faulty water pump: The water pump circulates coolant. A malfunctioning pump can lead to overheating.
* Head gasket failure: This is a much more serious issue and will require professional repair. It's indicated by white smoke from the exhaust, milky oil, or excessive coolant loss.
* Thermostat failure: A stuck closed thermostat will prevent coolant from circulating properly.
* Cooling fan malfunction: The cooling fan helps dissipate heat; if it's not working, the engine can overheat.
What you should NOT do:
* Ignore the warning light: Continuing to drive with an overheating engine can cause severe damage, including a blown head gasket, warped cylinder head, or even a cracked engine block – all very expensive repairs.
* Add cold water to a hot engine: This can cause the engine block to crack. If you must add fluid, use the correct coolant mixture.
* Open the radiator cap while the engine is hot or even warm: The pressure inside the cooling system can cause serious burns.
Next steps:
* Call a tow truck or roadside assistance: Get your car towed to a qualified mechanic. Do not attempt to drive it until the problem is diagnosed and fixed.
* Have a mechanic diagnose the problem: A mechanic will be able to pinpoint the cause of the overheating and perform the necessary repairs.
Ignoring this warning light could lead to costly engine damage. It's crucial to address it immediately.
