Safety notice
If temperature is in the red, you see steam, or the check engine light is flashing — pull over safely, shut off the engine, and do not open a hot coolant cap.
Symptoms
Why Is My Car Overheating?
Overheating causes and urgent safety steps.
Reviewed 2026-06-18
Key takeaways
- Pull over and shut off the engine if the gauge is in the red.
- Never open a hot radiator cap — scalding coolant under pressure.
- Low coolant, leaks, and stuck thermostat are common causes.
- Repeated overheating can warp heads and blow gaskets.
Safety first
If temperature spikes or steam appears, pull over safely, turn off the engine, and wait at least 30 minutes before opening anything. Do not pour cold water on a hot engine block. Call roadside assistance if unsure.
Common causes
Low coolant from external leak or internal consumption, stuck-closed thermostat, failed electric fan or fan clutch, clogged radiator, broken water pump, or collapsed hose. Head gasket failure shows white exhaust and coolant loss — overheating repeats quickly.
Low coolant
Check overflow reservoir when cold — not the pressurized cap. Pink, orange, or green fluid on the ground indicates leak location. Pressure test at a shop finds slow seepage.
Thermostat stuck closed
Engine heats fast from cold, upper hose stays cool while lower is hot — classic sign. Replacement is routine but diagnose before guessing.
Radiator and fan
Fan should run in traffic or when AC is on. Debris between AC condenser and radiator blocks airflow. Flush only when manual recommends — improper flush can cause leaks in old systems.
Water pump
Weep hole drip, grinding bearing noise, or play in pulley. Timing-belt-driven pumps are often replaced with the belt service.
Head gasket warning
Milky oil cap, bubbles in radiator, white smoke, and sweet smell — stop driving and tow for diagnosis. Continuing can destroy the engine.
Frequently asked questions
Can I drive to the next exit?
If no steam and gauge is only slightly above normal, idle with heat on full to shed heat and exit carefully. If in the red or flashing, stop immediately.
Does AC make overheating worse?
AC adds heat load. Turn AC off and use heater on full to help until you can stop safely.
Sources
- AAA overheating advice
- Owner manual
Informational only — not a substitute for a qualified technician. How we verify guides