Skip the auto shop - Our mechanics make house calls

Q: Fan never stops.

asked by on

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.

A: Hey there, thank you for asking about your ...

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?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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

Q: My Mercedes 2009 CLS 550 will crank but wont start

First, try using an alternate key. If it starts easily with a different key, then the original key needs to be reprogrammed. If the problem persists with either key, then it could be the ignition switch or possible a fuel...

Q: overheating no cooling fans

The relays are turned on by the Powertrain Control Module (PCM) by grounding the control wire of the relays. The PCM needs input from the engine coolant sensor above the water pump to sense whether the engine is overheating before...

Q: My GMC Acadia 2013 is blowing hot air and the AC is on

Unfortunately your 2013 GMC Acadia is known for having bad rear evaporator cores. So that sounds about right. I can't comment on needing the blower motor though. Does the rear air blow at all? These cars are also known to...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...