S212 interior road noise

[W1ghty]

Do you think with a saloon , just sound deadening behind the rear seats and the underneath of the parcel shelf will isolate all boot noise ?

 

[Larkone]

You need to reduce noise around the whole boot area because it acts like a big speaker box. It will help doing what you suggest but if you can reduce the amount of noise reaching the parcel shelf/ rear seat barrier you are then ahead of the game. I assume the E has the same plastic spare wheel tray and that is a bad source of noise.

 

[MikeInWimbledon]

@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?

Job done: A3 at both 70mph AND 50mph: averaging 77dB, in a range of 75 - 80dB.
(the noise goes mildly up when the engine is pulling and goes mildly down when the car is cruising)

A3 at 30mph: roughly 65 dB
At tickover / rest: 55dB

For what it's worth, I don't think the retractable cover makes any difference to road noise, but it can make a difference to noise from the contents of the boot - for example a rattly set of golf clubs is more noticeable if the retractable cover is rolled back.

As Larkone says, a loose spare wheel can make a noise in the "well." I had an E350 CGI S211 that initially had a noise from the spare wheel until I tidied it up.

 

[W1ghty]

You need to reduce noise around the whole boot area because it acts like a big speaker box. It will help doing what you suggest but if you can reduce the amount of noise reaching the parcel shelf/ rear seat barrier you are then ahead of the game. I assume the E has the same plastic spare wheel tray and that is a bad source of noise.

Yep plastic spare wheel tray . I saw it the other day when I was drying the boot out after finding a leak which I think was coming via the rear light clusters . Once I’ve confirmed a dry boot space I might move onto soundproofing .

 

[Larkone]

You can easily tell how bad it is for noise by tapping it with your knuckles. That is the method I used on all panels I treated - if it boomed, rang or rattled it got done. Once done it should produce a dull thud.

 

[Gazwould]

Exactly my method too , blanket covering with the initial damping mat is heavy and wasteful .

 

[phobos]

Interesting results on the S212 E500, as it looks like I am not too far off in terms of values, considering that mine is a diesel and it has 167k miles..
Extra sound deadening is most likely the way forward.

I have compared the dB value on the auto-decibel-db.com site and both the the 2009 E350 CDI and the S500 ( 2008 - W221) have very similar values, which I found hard to believe as I was convinced that the S class would be quieter.
@MikeInWimbledon - not wanting to abuse your kindness and good will, but as you also have a W221 based car ( and uber lovely one) if / when you can it woldbe interesting to have values of the same run.

@Larkone - when you did the wheel arches, did you put sound deadening inside the car or on the outside, by removing the wheel arch cover?

 

[MikeInWimbledon]

I have compared the dB value on the auto-decibel-db.com site and both the the 2009 E350 CDI and the S500 ( 2008 - W221) have very similar values, which I found hard to believe as I was convinced that the S class would be quieter.
@MikeInWimbledon - not wanting to abuse your kindness and good will, but as you also have a W221 based car ( and uber lovely one) if / when you can it woldbe interesting to have values of the same run.

On it like a bonnet: I'd already planned to get you that reading tomorrow from the W216.
From memory, I would have said that my 2007 W221 S500L was quieter than the 2004 S211 E500 that I owned before it arrived.
The C216 has the advantage of being a closed "box" with double-glazing. We'll see what the readings are tomorrow.

Apart from the changes to the bodies, the engines and gearboxes are each gradually updated. The C216 is the 4.7 bi-turbo, compared to the S212's 5.5 litre.

As a long time owner of estates (E46, E39, Saab 9-5, E91, E61, S211, S212) , I know the extra noise inside their coffin space. I'm not convinced about the need the spend money on sound deadening materials. I'd still counsel trying an extra couple of rugs on the floor, and stuffing some packing material into the wheel well / underfloor storage, I have a heavy duty Police reflective yellow jacket stashed under the floor,

 

[gianton]

On my S204 at 70mph I get 65 to 70 db on a good road. My Michelins PS4s have 30k miles on them.

 

[MercedesDriver]

As others have said try filling the well next to the tyre. I’m using that space as a water bottle (0.33litre) storage for the kids and the booth cover is always on so can’t really complain about the noise. Same size tyres as yours but Pirellis. Try that first.
My Mini Cooper was VERY loud and after filling the well with tyre repair kit the noise was gone.

 

[phobos]

On my S204 at 70mph I get 65 to 70 db on a good road. My Michelins PS4s have 30k miles on them.

Different tarmac in Greece, I would say. The Portuguese roads have different tarmac compared to the UK ones, and even on my father W211 the noise different was quite noticable, where at the same sames the W211 was much quieter than my S212.

 

[phobos]

As others have said try filling the well next to the tyre. I’m using that space as a water bottle (0.33litre) storage for the kids and the booth cover is always on so can’t really complain about the noise. Same size tyres as yours but Pirellis. Try that first.
My Mini Cooper was VERY loud and after filling the well with tyre repair kit the noise was gone.

Will stuff some duvets in there and test, thank you!

 

[phobos]

On it like a bonnet: I'd already planned to get you that reading tomorrow from the W216.
From memory, I would have said that my 2007 W221 S500L was quieter than the 2004 S211 E500 that I owned before it arrived.
The C216 has the advantage of being a closed "box" with double-glazing. We'll see what the readings are tomorrow.

Apart from the changes to the bodies, the engines and gearboxes are each gradually updated. The C216 is the 4.7 bi-turbo, compared to the S212's 5.5 litre.

As a long time owner of estates (E46, E39, Saab 9-5, E91, E61, S211, S212) , I know the extra noise inside their coffin space. I'm not convinced about the need the spend money on sound deadening materials. I'd still counsel trying an extra couple of rugs on the floor, and stuffing some packing material into the wheel well / underfloor storage, I have a heavy duty Police reflective yellow jacket stashed under the floor,

Thank you soo much!
Will get some old duvets and stuff them spare wheel well and on the sides and see if there is any difference.
Might only get the chance on Saturday ( as the SPL meter will get delivered on Friday) but I will get it done!

 

[Larkone]

@Larkone - when you did the wheel arches, did you put sound deadening inside the car or on the outside, by removing the wheel arch cover?

At the rear I did both sides and just under the wheel arch at the front.

 

[MikeInWimbledon]

Job done: A3 at both 70mph AND 50mph: averaging 77dB, in a range of 75 - 80dB.
(the noise goes mildly up when the engine is pulling and goes mildly down when the car is cruising)

A3 at 30mph: roughly 65 dB
At tickover / rest: 55dB

For what it's worth, I don't think the retractable cover makes any difference to road noise, but it can make a difference to noise from the contents of the boot - for example a rattly set of golf clubs is more noticeable if the retractable cover is rolled back.

As Larkone says, a loose spare wheel can make a noise in the "well." I had an E350 CGI S211 that initially had a noise from the spare wheel until I tidied it up.

CL500 numbers: A3 at both 70mph AND 50mph: averaging 62dB, +/- 3dbs
(the noise goes mildly up when the engine is pulling and goes mildly down when the car is cruising)
At tickover / rest: silent (Stop / start tech, obviously)

So, yes, significantly quieter than the S212, as expected.

But, dear lord, this is a path the madness. The C216 is much quieter in terms of suspension and motor noise, but there's extra wind noise from the pillar less design. So you've got different noises going on. And when you start listening, you hear little zizz es that you didn't hear before.

 

[phobos]

Wow.. what a difference, 15dB delta... that IS quiet..
Do you have 18s or 19s on the C216?
Should have got a S class If only the did an estate versio
Got the dB meter today so will be doing some tests into the weekend ( with / without the duvets in the boot) and report back

 

[MikeInWimbledon]

C216 is running on 20's, which I hate and will downsize at some point. By 2013, CL500's were on 19's or 20's. On 19's I suspect it would be quieter.
I used to have an S500L, ex a well-known foreign "playboy" King, and I suspect that was even quieter (no pillar-less wind noise, and 17" limo wheels)
Would still have one now but they're not a wife-friendly length and private owners don't need that Limo length.

 

[phobos]

I was about to say the same, a W221 ( SWB )with 17 inch wheels ( profile 55) will be super quiet and confortable
It might be a fun project to see to see how quiet I can get the S212 to be ;-)

 

[MikeInWimbledon]

I was about to say the same, a W221 ( SWB )with 17 inch wheels ( profile 55) will be super quiet and confortable
It might be a fun project to see to see how quiet I can get the S212 to be ;-)

A fine fettling project, for sure.

To the S212's credit, I don't think it's noisier than its estate car competitors, it's just a feature of that cathedral-like interior.

(Well, that's what I told the policewoman when she found that Choirboy in the back)

 

[phobos]

A fine fettling project, for sure.

To the S212's credit, I don't think it's noisier than its estate car competitors, it's just a feature of that cathedral-like interior.

(Well, that's what I told the policewoman when she found that Choirboy in the back)

I am sure the policewoman was very understanding