Whirring noise

[kusanku]

I have now had my 211 for a few weeks, and am still getting used to it, but generally very happy. Quite a lot more electrics and automatic things than the 210, e.g. wing mirrors, wipers, lights etc.

Speaking of which, there is one sound that I have not identified as yet. It seems to be an occasional whirring or humming noise, coming from behind the steering column/dashboard area. It sounds like some type of electric motor engaging for around 3 seconds at a time, and is noticeable quite regularly when doing stop/start driving in traffic. Usually hear it in the first few seconds after starting the engine as well. It may occur when driving, but it is not particularly loud, and could easily be hidden by engine and road noise.

Everything on the car seems to work, and it drives beautifully, so I am not jumping to the conclusion that it is the sign of a fault. I just wondered what it might be? Any ideas? Could it be related to the SRS braking system, as some posts have mentioned that this makes odd noises?

 

[BlackC55]

Sbc

 

[kusanku]

Thank you for this information. SBC is the braking system, rather than SRS as I stated in my previous post. This is the system they are dropping because they have had a high number of recalls. So I take it that this noise is likely to be related to the normal function of the SBC system?

 

[wadeyblue]

I get an almost identical noise, low revs and more so when engine is cool It is not apparent everytime I start the engine??
Any luck with the answer I am very interested.
E class w211 e280 2008 diesel.
Cheers
wadeyblue

 

[KillerHERTZ]

I get an almost identical noise, low revs and more so when engine is cool It is not apparent everytime I start the engine??
Any luck with the answer I am very interested.
E class w211 e280 2008 diesel.
Cheers
wadeyblue

See post #2

 

[JasM]

See post #2

Facelift 211's don't have SBC.

 

[Dryce]

Thank you for this information. SBC is the braking system, rather than SRS as I stated in my previous post. This is the system they are dropping because they have had a high number of recalls. So I take it that this noise is likely to be related to the normal function of the SBC system?

The pump operates to charge the pressure in the braking system. It sometimes activates when you open the driver's door to prep the system. While driving it operates from time to time. Noise varies depending on model - right hand drive cars were apparently worse (noise sometimes described as a groan or long fart). There were some minor mods to reduce this. Some drivers notice it more than others.

 

[wadeyblue]

Thanks for all these.
Additional info:- If the engine is running and I can clearly hear the whirring noise inside the car. IF I then lift the bonnet I cannot hear it when I stick my head under the bonnet.
Does this make sense????

 

[Dryce]

Thanks for all these.
Additional info:- If the engine is running and I can clearly hear the whirring noise inside the car. IF I then lift the bonnet I cannot hear it when I stick my head under the bonnet.
Does this make sense????

Could it be coming from the heating/aircon system?

 

[wadeyblue]

Not heating or aircon, still there when these are totally switched off.
Changes tone sometimes when I turn the steering wheel which makes me think it is the pump but again no noise from pump when head stuck under bonnet.Wife says it sounds like something slipping at low revs and starts to catch as revs go over 1000rpm. What does she know LoL But just as good as anything I have come up with so far.

 

[Dryce]

Not heating or aircon, still there when these are totally switched off.

These can make intermittent noises even when the car is switched off as the system adjusts itself. There are presumably small fans and motorized valves.

 

[Troon]

Just to re-iterate post#6: a 2008 E-Class does not have SBC, so it's not that making the noise.

SBC was dropped at the June 2006 facelift on W211 E and W219 CLS.

 

[wadeyblue]

Finally found out what was causing my whirring noise. Steering fluid level was a wee bit low. Topped it up and yipppeee no whirring noise at all.
Should have checked this earlier, better late than never.

 

[B11R]

Thanks for this, I've got an '07 W211 e280 which has just started exhibiting this noise so I'll check the steering fluid.
My car is serviced every year by Mercedes, do they not check and top up the fluid if needed?

 

[Petrol Pete]

Great thread revival !! 12 years . Welcome.

It should be on the service schedule as many MB's have the filter moulded inside the expansion tank , which itself is a disposable service item. It would be easy for any garage just to vac the fluid out of the tank , replace it and just top it back up. Your car might be different.

That would not be a fluid change . It is (in my opinion) a service that is often missed. Open the tank have a sniff , if it smells funky/burnt and is neither green or red it's time to flush.

MB use two fluids green or red , my car is a 2006 and uses green , there is about a litre in the system and it works pretty hard so for me replacing it as required is cheap insurance against buying a new pump or steering rack. Getting the correct fluid is IMHO crucial.

It would not surprise me if the fluid in your PAS system is either original or many years old.

 

[B11R]

My car is with Mercedes to check it over now, will let you know the outcome.