Roaring fan noise coming from engine bay

[tazkhan786]

I have a 2004 C Class Coupe and I have just noticed today, when stationary and turn the car on, after about 30 seconds you can hear loud fan noise coming from the engine bay.

The vehicle has been recently MOT'd and serviced, what can the problem be

Hope someone can shed some light, as it is worrying me. :-|

(Additionally: When moving off in 1st gear, car judders/vibrates...?)

 

[Irresistance]

Regarding the vibrations and assuming it is an Automatic:

1) Does it "thud" or clunk when you engage "D" or "R"?
2) When you switch the engine off, does it rock/shake the car?

If so, your engine mounts are up for replacement. This has no relation to the loud fan noise btw. That sounds like an electrical problem in the temperature system. Was the car very warm when you switched it on when it happened, or from cold start?

 

[Rappey69]

Have you got the air con/heating on.. That will kick the fan into life.

 

[turbopete]

Have you got the air con/heating on.. That will kick the fan into life.

although i wouldnt have thought you would be able to hear it!

 

[Rappey69]

Can hear it at low speed or stationary..

 

[Naraic]

Air pump...this is a petrol car.

 

[tazkhan786]

Sorry forgot to mention:

6 speed Manual/Petrol.

With heating/fan off still can hear it, it is coming from the engine bay, front.

When I switch the car off, the fan sound goes after 5-10 seconds after.

 

[tazkhan786]

Also noticed today at 8am, on the LCD temperature was showing 85 degrees celsius!

 

[rayhennig]

Also noticed today at 8am, on the LCD temperature was showing 85 degrees celsius!

Sounds like a duff sensor telling the system that it's 85C and the fans better go on. My old 300CE (separate sensor for fans and readout) did that when I first got it and they changed the sensor. Thereafter the fans only come on when the engine reaches 105C.

Possible? Cheap fix if it is.

RayH

 

[Naraic]

Sorry forgot to mention:

6 speed Manual/Petrol.

With heating/fan off still can hear it, it is coming from the engine bay, front.

When I switch the car off, the fan sound goes after 5-10 seconds after.

Why not open the bonnet and actually pinpoint what is making the noise.?

 

[L John]

My 2008 C class did the same thing (fan noise, not the 1st gear judder), it sounded like a strong fan shifting a lot of air so I assume it was the electric fan for cooling the radiator, even though the engine was cold.

Took it in to MB and they said they sorted the problem by loading new software.

 

[tazkhan786]

Why not open the bonnet and actually pinpoint what is making the noise.?

It is coming from the fan located at the front of the engine. When I hover my hand over it, I can feel the breeze.

 

[tazkhan786]

Thanks for all the replies so far.

 

[tazkhan786]

Today, after driving 6miles, opened the door, when I shut the engine off, it took atleast 10seconds after engine shut off for the fan to turn off.

 

[alexanderfoti]

Today, after driving 6miles, opened the door, when I shut the engine off, it took atleast 10seconds after engine shut off for the fan to turn off.

Is the engine temperature showing 85 deg c the whole time?

 

[tazkhan786]

Yes, showing 85 degrees on a cold morning and even after driving on the M1 for an hour.

BTW: Is the temp display engine temp or outside temp? If outside temp, it certainly isn't 85 degrees

Car drives well though....

 

[television]

The outside temp is the one that shows after you turn the key to ignition on, just a little LED window, they normally show 37 or 38c when the outside probe has failed

 

[tazkhan786]

Just to be clear, I am referring to the LCD screen after scrolling past CD player info, mpg etc - this is showing as 85.