Symptom guide
Car Overheating
What to do when the temperature gauge rises and how to narrow down cooling system causes.
Quick answer
Overheating is usually caused by low coolant, leaks, thermostat failure, radiator fan problems, water pump issues, or blocked airflow.
Most likely causes
- Low coolant from a leak
- Stuck thermostat
- Radiator fan not working
- Water pump failure
- Blocked radiator or airflow
Basic driver checks
- Turn off AC and turn cabin heat on if you need a short safe pull-over.
- Look for steam or coolant smell.
- Check coolant level only after the engine cools.
- Notice whether overheating happens in traffic or at highway speed.
DIY diagnostic path
- Do not remove the radiator cap while hot.
- Check for dried coolant residue around hoses and radiator.
- If fans do not run in traffic, fan circuit diagnosis is needed.
- If overheating happens at speed, check coolant flow and radiator condition.
Common mistakes
- Adding cold water to a severely hot engine without caution
- Driving repeatedly after overheating
- Replacing the thermostat without finding coolant leaks
What to tell the mechanic
Say when overheating happens: idle, traffic, highway, towing, or AC on. Ask for pressure test and fan operation check.