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Radiator Fan Runs After Switching Off

The cooling fan running for a few minutes after switch-off is often normal on a hot day or after a diesel regeneration; running for a long time or always can mean a sensor or relay fault.

Normal risk

Usually normal. Have it checked if the fan runs for a long time every time or drains the battery.

Short answer · Is it normal for the fan to run after the engine is off?

Many cars run the fan after switch-off to cool the engine and turbo, especially after hard driving, in hot weather or after a DPF regeneration. If it runs every time for a long time, even when cold, or does not stop, suspect a temperature sensor, fan relay or control module fault.

On this page

Safe checks you can do

  1. Note the conditionsHot day or hard drive: normal. Cold engine: not normal.
  2. Check the temperature gaugeOverheating while driving needs attention.
  3. Time itA few minutes is typical; much longer is not.

Questions that narrow it down

  1. Did you just drive hard or in heat?Normal after-run.
  2. Diesel with DPF?After a regeneration.
  3. Does the battery go flat?Fan relay stuck.

Possible causes

Listed without ranking. Use the questions above to see which ones fit your car.

  1. Normal after-runCooling engine and turbo.
  2. Coolant temperature sensorWrong reading.
  3. Fan relay stuckFan never stops.
  4. Fan control moduleFaulty control.

Questions about Radiator Fan Runs After Switching Off

Can the fan drain the battery?

A short after-run cannot; a stuck relay can.

Should I open the bonnet?

Keep hands away from the fan; it can start at any time.