Car is overheating

Symptoms

• Temperature gauge needle in the red or climbing fast
• Steam from under the hood
• Warning light or chime for engine temperature
• AC blowing warm as the engine struggles

Likely causes

• CommonLow coolant from a leakCoolant loss reduces the system's ability to absorb and move heat away from the engine.
• CommonStuck thermostat (closed)A thermostat stuck closed blocks coolant flow to the radiator entirely.
• CommonFailed radiator cooling fanWithout the fan pulling air through the radiator, the engine overheats especially at low speed or idle.
• PossibleFailing water pumpA worn pump impeller or belt failure stops coolant from circulating.
• PossibleRadiator clogged internally or externallyBlocked fins or internal buildup reduce the radiator's ability to release heat.

What to do

1. Pull over safely as soon as you notice the gauge climbing into the red or see steam; do not keep driving.
2. Turn off the AC and turn the heater to full hot, which pulls some heat away from the engine temporarily.
3. Shut the engine off once safely stopped and let it cool for at least 15–20 minutes before opening the hood.
4. Once cool, check the coolant reservoir level (not the radiator cap, which can be dangerous under pressure) and look for obvious leaks or puddles.
5. If coolant is low and you have some on hand or water as a temporary measure, add it to the reservoir once the engine is cool, not hot.
6. Listen for the cooling fan running once the engine is back on; if it never comes on, that's a likely cause.
7. Do not resume driving if the gauge climbs again quickly; have the vehicle towed instead of risking engine damage.

Tools and parts

• Coolant or water for emergency top-off
• Gloves
• Flashlight

When to call a pro

See a mechanic if the cause isn't an obvious, easily fixed low coolant level, especially if overheating happens more than once, since continued overheating can warp the engine or blow a head gasket.

Safety