Engine overheating
General info, not professional advice. These are common causes that apply to most cars, not a diagnosis of yours. If you are unsure or a problem affects brakes, steering, airbags or fuel, see a qualified mechanic.
Likely causes (most common first)
- Low coolant from a leak
Puddles under the car, a sweet smell, or a low reservoir.
๐ Find a used radiator hose - Cooling fan not running
It overheats in traffic or at idle but is fine on the highway.
๐ Find a used radiator fan - Stuck thermostat
Temperature climbs fast, or the heater blows cold while it's hot.
๐ Find a used thermostat - Failing water pump
Leaks or noise near the pump, or overheating.
๐ Find a used water pump - Clogged or leaking radiator
Leaks, or the temperature creeps up under load.
๐ Find a used radiator
Quick safe checks
- If the gauge goes into the red, pull over safely and shut off the engine.
- Once it's fully cool, check the coolant reservoir level.
- Look for wet spots or crusty residue on hoses, the radiator and the water pump.
- With the A/C on, the electric cooling fan should usually run. If it never does, suspect the fan, relay or fuse.
Safety first
- โ ๏ธ Never open a radiator or coolant cap on a hot engine. Hot coolant is under pressure and can cause severe burns. Wait until the engine is cool.
- โ ๏ธ Keep hands, hair and loose clothing away from belts and the cooling fan. The fan can turn on even with the engine off.
- โ ๏ธ Many automotive fluids are toxic. Antifreeze tastes sweet to pets. Clean up spills and dispose of fluids at a recycling center.
When to see a pro
It overheats repeatedly, you see white exhaust smoke or milky oil, or coolant disappears with no visible leak. These can mean head gasket trouble.