Radiator fan not working: overheating in traffic but fine on the highway

Searchers for “overheating in traffic” but “fine on the highway” usually have airflow without a fan at speed, and none when stopped. That pattern is classic fan failure.

Checks the workshop runs

• Fan motor and resistor/PWM module
• Fan relay and fuses
• Coolant temperature sensor readings
• AC request that should force the fan on

What you should do

If the gauge rises in a jam, switch the heater to hot/full to shed heat, idle carefully, and stop before the red zone. Do not remove the cap hot.

Book a cooling or diagnostics slot on CarFix before summer holiday traffic.