S212 interior road noise

[phobos]

Hi,

I wonder if anyone can shed some light on the issue that has been annoying me for months now.

My S212 which I really found off, seems excessively loud inside the cabin, whereas i can hear a lot of road noise. Though it could be my old Kumho tyres getting worn, so I got 4 new Goodyear Eagle F1 245/45/R17.
The tyres are inflated as per manufacturers guidelines and I cannot see any issues with door seals.

Still, it is really loud specially on motorway speeds of 70 mph, where i measure around 80 to 85 dB while crusing ( measured with an iPhone with dB X app)
The car has Airmatic and sport / confort suspension modes makes no difference.

An interesting note:

the noise seems to come from the rear of the car.

When stationary and engine idling, I have measured the noise levels on the front and rear seats, and the most quiet that I got was around 70 dB on the rear passenger seat ( behind the front passenger seat) with position being 77dB onwards.


Any thoughts?
Many thanks

 

[W1ghty]

You could stick some Dynamat under the rear boot space carpet to absorb sound .
What tyre pressures are you using ?
Try laying a duvet in the rear boot space as a test to see if the sound Is affected at all ?

 

[phobos]

Hi Wighty,

I am using 34 psi front and back.

The car came with a boot mat, which is around 5mm thick, but I can put some more in there to see if makes a difference.

Do you have estate or a sedan?

 

[W1ghty]

Hi Wighty,

I am using 34 psi front and back.

The car came with a boot mat, which is around 5mm thick, but I can put some more in there to see if makes a difference.

Do you have estate or a sedan?

Saloon over here buddy . Those tyre pressures won’t cause any noise problems . Be interesting to see if the sound changes when there is more stuff in the boot area .

 

[MikeInWimbledon]

Difficult to comment on, without actually hearing it, but the one comment I would make is that all estates are noisier, by definition, than their saloon equivalents. Basically you've got a big open box behind you which doesn't muffle the noise of the rear axle and wheels. (I say this having owned BMW E39, and E91's, as well as S211's and an S212.

Contis are famous for being "accused" of being noisy, although I can't say that I've really noticed, and I've used them regularly. I can't remember anyone talking about Eagles and noise.

Do you think your estate has got noisier, or do you just think it is noisy?

In general the S500 and the CL500 are both much quieter than the S212, but that's hardly a surprise for limo style vehicles with double glazing.

 

[phobos]

I will fill my boot of duvets and test it.
At least I will have a fun picture of a boot full of duvets

@MikeinWinbledom - I think it is just noisy, but before I blamed it on the tyres. Also, I see you have the lovely E500 S212. If you can and take it for a spin on the motorway, would you be so kind as to measure the dB at 70mph?

Many thanks to everyone so far

 

[MercedesDriver]

Never measured the noise level in my S212 but have noticed the difference with the stretched booth cover.

 

[phobos]

Never measured the noise level in my S212 but have noticed the difference with the stretched booth cover.

I assume that the noise levels were lower with the stretched boot cover covering the entire boot floor?

 

[MercedesDriver]

I assume that the noise levels were lower with the stretched boot cover covering the entire boot floor?

Yup.

 

[Gazwould]

Estates especially in the rear act as a resonace box.


The answer is add...

Some cars have reasonable OE noise damping.



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[Headhurts]

I have an S212 2016 model with the 3.0 litre V6 diesel, I personally find my car extremely quiet although of course road surface makes a huge difference.

80 + decibels does sound high, mine is shown as around 63 + at 70 mph but not sure if this is the saloon or estate the source being as below, quite a useful site I think.

Mercedes E

Robin

 

[phobos]

@Headhurts - the site is a great find - thank you.

Estates especially in the rear act as a resonace box.


The answer is add...

Some cars have reasonable OE noise damping.
View attachment 103551


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Fine in adding but I think I have a problem that needs solving first as it is way to high from standard
Guess i will need to

 

[phobos]

Sorry, brain fart on my last message.

I am happy to add an extra sound deadening layer but first I will try the following as I think that something is not right.

a) add some duvets to the boot
b) seal off the doors with masking tape to ensure that no noise is coming from there.

Hope fully I will be able to do these tests during the weekend and than I will report back.

Many thanks to everyone!

 

[Larkone]

In my W219 when I upgraded the sound proofing and sound deadening the biggest single improvement was treating the plastic spare wheel tray in the boot - made a huge difference adding both to this area.

The other areas that made a significant difference was taking out the wheel arch liners and treating the metalwork behind with 6mm sound deadening mat.

 

[Gazwould]

Yes wheel arches are massive noise generators .

 

[phobos]

In my W219 when I upgraded the sound proofing and sound deadening the biggest single improvement was treating the plastic spare wheel tray in the boot - made a huge difference adding both to this area.

The other areas that made a significant difference was taking out the wheel arch liners and treating the metalwork behind with 6mm sound deadening mat.

Hi Larkone, which product did you use?

 

[phobos]

Yes wheel arches are massive noise generators .

Definitely, mine ,as MikeinWimbledon suggested , being inside the cabin are even worse.. Will run through the tests soon and report back. Got a SPL meter on order as well so I can make semi accurate measurements

 

[MikeInWimbledon]

I will fill my boot of duvets and test it.
At least I will have a fun picture of a boot full of duvets

@MikeinWinbledom - I think it is just noisy, but before I blamed it on the tyres. Also, I see you have the lovely E500 S212. If you can and take it for a spin on the motorway, would you be so kind as to measure the dB at 70mph?

Many thanks to everyone so far

Happy to. I'll be using DB Meter.

70mph on on the A3.

In my lovely, low mileage, high specification, 2010 E212 estate, currently for sale, much to my wife's annoyance ..... (see Classifieds)

 

[Londonscottish]

I went from S202 estate to S211 to S212 and they just got quieter and quieter. The latter two on Air.

The next time I go somewhere in the 212 I'll try to remember to take a measurement. But no trips planned in the immediate future.

 

[Larkone]

Hi Larkone, which product did you use?

Silent Coat for deadening Silent Coat Vehicle Sound Proofing
and
MLV for sound proofing Dodo Barrier MLV Large Sheet

I ended up doing the doors, under and behind the rear seat, wheel arches and boot - nice and quiet now and the sound system (upgraded speakers) definitely improved