Normal grating noise on C200k

[tony0710]

Dear All

I have a 2002 C200k SE auto elegance sal with Xenons.

I have been complaining of a loud grating noise that can be heard from within the car, only present when the engine and weather is cold.

The grating noise is like pulling a shower hose through a metal ring - a rachet grating noise!!!

It can be heard by placing the key into the ignition and turning the key to the second position. As soon as youturn the key into the second position - you will hear the grating noise. I admit that a low level grate can be heard and I feel that is acceptable, but to hear a loud audible noise is not acceptable!!!

The noise can be heard, even with the lights manually switched off, and turning the key to the second position.

The MB dealers have looked into it 3 times and have concluded that it is normal!!! I don't beleive this a all!!!

Does anyone else have the same problem with thier car??

All feedback much appreciated.

Tony.

 

[fuzzer]

Maybe the climate control opening up the vents?

 

[Maff]

Fuel pump maybe having a problem?

 

[pluggers]

I'd go for the fuel pump as well.Sounds like its struggling to prime the system or shaking on its mounts.

 

[Brian WH]

Originally posted by tony0710
The MB dealers have looked into it 3 times and have concluded that it is normal!!! I don't beleive this a all!!!
Tony.

If it is "Normal" ask them what it is?

Then we can comment more to tell you whether it is normal on similar cars. OK?

 

[Stratman]

The MB dealers have looked into it 3 times and have concluded that it is normal!!! I don't beleive this a all!!!

Alternatively, if it's normal, ask them to show you all the cars on their forecourt making the noise!

 

[jimmy]

You mention that you have Xenons and then you say something about the noise still present when you manually switch the lights off. Am I right in thinking that you think the noise is connected to the lights? If so I presume the Xenons have a self levelling system, must be electrical/mechanical on the 202's the manual levelling operates via vacuum.

Where is the noise coming from?

Could it be the climate control temp sensor fan? These tend to get noisy on the 202's, it is very near to the rear view mirror.

Stabbing in the dark really, we need more info about where the noise is coming from.

 

[tony0710]

Dear All

Thanks for the input so far!

The noise actually does appear to be coming from the driver side headlamp area.

MB Dealers have said that this "noise" is normal for Xenon style headlamps, that is what I cannot believe!!!

So what I really wanted to know is, if anyone else that has Xenons - have heard this "noise"???

As for the other suggestions I will look into those aswell.

Thanks again, much appreciated.

Tony

 

[pepe]

Not sure if its a similar thing to this, but on mine (1998 c250td) when i turn the ignition off i get a noise from this thing pictured below (just under the airbox behing front drivers headlight) Its not very loud at all, in fact you only really hear it if the bonnets open, i can only describe it as like a rattlesnake and it gets slower and slower until after about 20 seconds it stops. kind of like a wind up toy winding down, but like i say you can hardly notice it. Dont suppose anyone knows what this actually does ??

 

[jimmy]

Originally posted by pepe
Not sure if its a similar thing to this, but on mine (1998 c250td) when i turn the ignition off i get a noise from this thing pictured below (just under the airbox behing front drivers headlight) Its not very loud at all, in fact you only really hear it if the bonnets open, i can only describe it as like a rattlesnake and it gets slower and slower until after about 20 seconds it stops. kind of like a wind up toy winding down, but like i say you can hardly notice it. Dont suppose anyone knows what this actually does ??

Mine has that too, it would though wouldnt it!

The EGR valve and turbo wastegate are operated via vacuum, the 'purring' noise you hear when the engine has stopped is the vacuum pulling air back in. There is a little air filter on the end of a pipe you can see.

 

[tony0710]

Thx Pepe,

I'll have to look into and perhaps actually try to isolate the exact location of the noise.

Like I've said, this noise is there all time; but when the car is cold and the weather is cold (late evening during the winter time) the noise is audilble from within the car with windows closed - in fact it is very loud!!! That is what i am really worried about!! A slight murmur is no problem, but when it is a loud grate - that is worrying!!!

Tony

P.S. I'll too try to take a pic of exactly where the noise is coming from, and post it - so watch this space!!!

 

[Dieselman]

It does sound like one of the headlamp adjusters is noisy and something is rubbing on the body so the noise is transmitted through the shell of the car.

 

[Brian WH]

Originally posted by Dieselman
It does sound like one of the headlamp adjusters is noisy and something is rubbing on the body so the noise is transmitted through the shell of the car.

So why does it do it when the lights are turned off????

 

[tony0710]

Dear All

After a lengthy discussion with the MB dealer service manager, it appears that the Xenons have a self levelling mechanism that is somehow "connected" to the suspension of the car.

The Xenons DON'T need to be ON for the self levelling mechanism to work.

It appears that when the car is switched on (headlights can either be off or on) the position of the suspension is detected by the self levelling mechanism of the Xenons; and there is a roller/ratchet mechism that "levels" the Xenons to the correct position in relation to the suspension.

I don't have the technical know-how of Xenons, so although the explanation appears to be plausible - I wonder am I being "palmed off" by the use of sophisticated technical "jibberish"?????

So I have been told that this is a design "fault" and that I have to learn to accept it and live with it!!!

Question that I asked is why it only occurs on the driver's side? Answer: well the main part of the mechanism is located on that side.

I'm no technical buff, but I get the feeling that I am being "palmed off"!!!

So for you technical wizards out here in forum - is the explanation true???

Tony.

 

[Dieselman]

Yes the explanation is correct.

See if the dealer will demonstrate this to you using another car. the noise is not uncommon, but if yours is noisier than others there must be a reason which can then be fixed.
The grating is because a stepper motor is used for the positioning and because it moves in very small steps of stop / start motion it makes a noise.
The positioner has to use a stepper motor so it knows how much adjustment has been applied.

I would have thought that each headlamp would have it's own adjustment mechanism, but hey, who knows

 

[tony0710]

Originally posted by Dieselman
Yes the explanation is correct.

See if the dealer will demonstrate this to you using another car. the noise is not uncommon ...... I would have thought that each headlamp would have it's own adjustment mechanism, but hey, who knows

I have asked the MB dealer to provde access to another car with Xenons so that I can "listen" for the noise - awaiting for reply as yet.

Yep I agree that each light should have it's own mechanism, that's what led me to beileve that I am being palmed off!! Obviously if one side is smooth and quiet, the other side should be too!!!

Thanks for all the replys.

Tony.

 

[Brian WH]

My Bi-Xenons do not make a noise.

 

[tony0710]

Originally posted by Brian WH
My Bi-Xenons do not make a noise.

Thanks Brian

That's exactly what I wanted to hear!!! But then again you have the superior E-Class, and I have a humble C-Class.

It would be beneficial for me if other C-Class owners on this forum, that have Xenons could let me know if their car makes a noise?

How to detect the noise:

1. Swtich off radio.
2. Place key into ignition.
3. Turn key once.
4. Turn key the second time.
5. Listen!!! You should hear the noise.

A low level murmur is acceptable as far as I am concerned, can't expect cars to totally quiet.

Try the above method when the engine is cold (first thing in the morning or last thing at night), as the weather will be cold at these times aswell. Is the noise louder?

I would be enternally grateful if C-Class owners with Xenons do this little test and let me know. Perhaps even other Class oowners would like to try the test and see what results the get - would be interesting.

Tony.

 

[tony0710]

Originally posted by Brian WH
My Bi-Xenons do not make a noise.

Thanks Brian

That's exactly what I wanted to hear!!! But then again you have the superior E-Class, and I have a humble C-Class.

It would be beneficial for me if other C-Class owners on this forum, that have Xenons could let me know if their car makes a noise?

How to detect the noise:

1. Swtich off radio.
2. Place key into ignition.
3. Turn key once.
4. Turn key the second time.
5. Listen!!! You should hear the noise.

A low level murmur is acceptable as far as I am concerned, can't expect cars to totally quiet.

Try the above method when the engine is cold (first thing in the morning or last thing at night), as the weather will be cold at these times aswell. Is the noise louder?

I would be enternally grateful if C-Class owners with Xenons do this little test and let me know. Perhaps even other Class oowners would like to try the test and see what results the get - would be interesting.

Tony.

 

[zerocool]

seems strange how it is affected by cold weather.
we have a lot of trouble with recurculting valve on the heater box making a loud clicking noise,which will be coming from behind the dash.
if you have auto air con,then these flaps will adjust automatically when the car is started from cold or even with the ignition on.
your local dealership should know this,if not should be checking their technical bulletins for this problem or other problems,failing that they can ring merc technical for further help on this.
don't let them palm you off,if it is the heater box or the headlight causing the prob then it should be renewed under warranty.
I have never heard of headlights making a noise like this,and if they are then something is wrong.