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Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 23082
Experience:  BEng hons Mech engineering, in auto industry 22 years
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The fan in the engine spontaneosly comes on making a loud

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the fan in the engine spontaneosly comes on making a loud noise while driving along the cuts out for a while and starts again.
when the engine is switched off the fan continues for a full minute and sometime longer before stopping. it sometimes the starts again before finally stopping.
the noise is really loud.


the engine cooling fan should cut and in out ? this is normal behavior especially if the car is moving slowly

now if the fan is coming on with a cold engine then thats a different matter and I'd 1st consider replacing the engine coolant sensor and also check the state of the wiring between the sensor and the engine loom - check it for chafe damage and hard sections indicating a short

Customer: replied 1 year ago.
the fan does come on at full blast shortly after the car is started, it then shuts off and then as I drive along it comes in again intermittently and the sound is much louder than the sound of the engine usually...for example if I stop at a traffic light.Is it ok to continue driving the car as it is for the time being?


I'd say as long as the engine isn't overheating then yes you're fine to carry on driving the car


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