What to do right away
Pull over somewhere safe and turn the engine off.
Don't open the radiator or coolant reservoir cap while the engine is hot. The coolant is under pressure and can spray out and burn you.
Let it cool, then check the coolant level in the reservoir. If it's low, look for drips under the car.
If you have to move the car a short way, turning the heater to full heat can pull some heat away from the engine, but get it checked before driving further.
Common causes
- Low coolant from a leak in a hose, the radiator or the water pump
- A thermostat stuck closed
- A cooling fan that doesn't come on, often noticed in traffic
- A failed water pump or a broken serpentine belt that drives it
- Old coolant or a clogged radiator
What we check
We pressure-test the cooling system to find leaks, check the thermostat, fan, water pump and belt, and read any engine codes. Then we tell you what failed and quote the repair before any work begins.