Q: Fan never stops.

asked by on September 08, 2016

Some times the fan starts and does not stop, it's sound like an airplane.

My car has 98777 miles.
My car has an automatic transmission.

Hey there, thank you for asking about your 2007 Mercedes-Benz CLK550. This is a common symptom of a failing coolant fan relay. This relay controls the cooling fans and cycles them on and off based upon temperature. When this relay is working intermittently or is faulty, it can cause the fans to come on randomly, come on and stay on, or sometimes not come on at all. This can be dangerous in the event they stop working altogether as it can cause the car to overheat. I would recommend having an expert from YourMechanic come to your home to diagnose the problem and replace the cooling fan relay if necessary.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

My engine fan is not kicking in, but my temp is between 80 -100. Is my thermostat bad because my check engine light just turned on

This can be caused by a number of things such a faulty thermostat, or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at...

Water pump

The 5.7 L engine on the 2007 Toyota Tundra has a timing chain, and the 4.7 L engine has a timing belt. If you have the model with a 4.7 L engine, you will want to purchase a timing...

2010 Mercedes C300. Car will start, but steering wheel is locked and red battery light is on dashboard

The battery warning light signifies an electrical problem and such could be in the battery, the alternator, the charging circuit or possibly (but less likely) elsewhere in the vehicle electrical system. There might be a relationship between the warning light...

Related articles

Symptoms of a Bad or Failing AC Fan Control Module
Common signs include cooling fans running for a long time or not at all, as well as weakened air flow. Without fixing, your car may overheat.
Symptoms of a Bad or Failing Water Pump (Auxiliary)
Common signs include no warm air or fluctuating heat coming from the heater, the window defroster not working, and high pitched buzzing sounds.
What Causes a Car to Overheat?
Several problems can make your car overheat. A leaky cooling system, blocked radiator, bad thermostat, or failed water pump are common causes.