1996 C200 Noise

[johnnyj]

Hi there
I recently bought a UK 1996 C200 Elegance, which I am really pleased with. It does have two areas that concern me, however:

The car seems to have a vibration type sound noticable at low speeds, which speeds up with engine revs. It is difficult to describe, but could almost be the sound of the radio antenna resonating through the car in the wind (but obviously it isn't). It isn't a whine, but is more like the sound of a brake disc rubbing, or a driveshaft. But I can't figure out where it is coming from, or what it is. It is not loud, but is noticeable as it is the only sound I can hear due to the engine being so quiet! Any ideas?

Secondly;When I start the car and for a good few minutes afterwards, there is an electrical noise (not unlike that made by the CD autochanger) coming from (what seems like, but can't be) the right hand rear light cluster.

The car has done a high milage at 144k, but has full MB dealer service history.

Should I be worrying about eaither of these sounds? The former is concerning me more!

Many thanks

John Jones
Northants

 

[guydewdney]

total guess - but vibration damper at the front of the engine? known issue with SOME mercs... its basically the front pulley...

electrical noise - hmmm - vacuum pump? but i think thats noher near there - so a vacuum leak at the petrol tank apature.. maybe a leak thre?

total guess - so ignore if you will

 

[MondeoMan]

My car is identical to yours. I had most of the inner boot panels out at the weeked (to fit an amp) and there is nothing in the right hand rear corner to make a noise. The central locking pump is to the right of the rear shelf, could this be it?

 

[johnnyj]

Hi Modeo Man (I just traded in my 3rd Mondeo for my Merc!!)

Many thanks. It is very strange. The sound is like an electric motor, pulsing for one second on, one second off. It is a soft, refined whir that sounds for all the world like it is coming from the o/s rear light cluster - which I know is impossible! I wondered if it is something to do with the petrol flap locking mechanism, which is sort of near there. Maybe the sound is traveling.

Thanks anyway!

John

 

[joe bloggs]

First noise could be the polybelt (fan bellt) they can make a bit of noise like you describe, we normally sprinkle some talk on them while the engine is running, shuts it up for a bit, and it smells lovely.

Other noise could be the central locking pump pulsing on and off, as I am sure it also provides vacuum for the heater servo's etc, Also possibly you have an air leak in your central locking somewhere, this would make the pump run for a while after unlocking.

Only other things in this area are 1 the battery, and 2 the electric window / roof control unit tucked behind the battery.

 

[johnnyj]

Noises - C200

Thanks all (and can I just say what a great forum this is?!!)

The first noise hasn't got any worse, but I do have a sneaky feeling that it shouldn't be there. It is very difficult to describe! A sort of low level "wow-wow-wow" sound - a bit like you'd get in a gale when the wind is reverberating through your TV aerial mast and into your chimney. It doesn't sound like traditional gearbox whine (of the Mini or Austin A60 variety!!) and isn't particularly metallic. Who knows.

The second sound (ostensibly from the rear o/s light cluster - yes, it really does sound like it is coming from there!!!!!) is a pulsing motorised sound, with rythmic similarities to the telephone engaged sound. It is always present when the engine is started, and continues for about three minutes, after which it stops.

The strange thing is, when I turn the CD player up , all annoying noises dissapear!!

Thanks all

John

 

[benzfan]

Have the vacuum pump confirmed as the source of the one noise immediately. It should not run for 3 min. but rather only a few seconds. If you have a leak, the pump will burn out by running too long and they are not cheap, as many have discovered.

 

[GeneralCuster]

If it's any help, my '96 C200 has a lot of "hiss" coming off the rear brake discs. Usually clears once you've been driving for a little while. I assume it's something to do with the metal corroding slightly when the car's stood, then being cleaned off as you brake more.

Mine also makes a slight "whining" resonance from the transmission/engine at around 60mph. But not at other speeds. I just tend to think, hey - It's a 9 year old car, so it's not going to be perfect, so as long as it's running as well as it does & not leaking a drop of anything, I'm happy!

 

[johnnyj]

Many thanks, that reassures me no end! Glad to hear that other owners get strange noises. I discovered that radio three helps, and when that is no good - Guns & Roses!!

Thanks again

JJ

 

[996jimbo]

Does the second pulsing noise from the rear begin as soon as the car is started or only when you move off? If it's to do with the central locking it would start when you are moving above a certain speed.

To check you can make sure the doors are all unlocked then start the car, close the doors and listen for the noise. Then operate the central locking switch and see if it starts and while you're at it check that the doors and boot do all lock.

Radio 3 / Guns & Roses. Hmmmm, to use Ken Bruce's favourite word - eclectic.

 

[johnnyj]

Hi jimbo

It starts as soon as the car is started (I think). What do you you reckon, this being so?

I might try Deep Purple, The Black Dyke Brass Band or Focus next (mmmmm - NICE!)

Cheers mate

John

 

[996jimbo]

I'm afraid I've exhausted my limited diagnostic skills - not a clue what it is!

I would suggest turning up the CD player again, but then you'd have to listen to what's playing. Perhaps the noise is the changer trying to scratch your Gun's 'n' Roses CD? Try and steer clear of American Rock and see if that helps. I do, and I haven't got the funny sound in my car!

 

[c13tay]

had a difficult to describe noise from my c180 - thought about belts etc - developed into a drone at motorway speeds.

Had it serviced on saturday - turned out to be a completely knackered fron wheel bearing