Just how quiet?...for an oil burner...

[Traveller]

Hi guys,

When we got our MB a few weeks ago (2002 C220 CDI Est. 34k miles, all the toys ) my wife had sat in the back of the car for a short journey into town, and she came out with what I thought was a rather astute statement, given she knows zilch about anything mechanical, including cars. She said, " I would have thought the car would have been more quiet at speed, given it's a MB."
I gave her comment no thought at all, until the other day when I was motoring down the M18, on reaching 70 mph the exhaust note turned slightly boomy, not terribly noisey, nevertheless there was a distinct rise in exhaust noise, between 70 and 75mph, thereby afterwards it seemed to subside to fairly quiet again upwards to 80 and 85 plus mph.
She wasn't there at the time, and I remember thinking back about what she'd said, and concluding, she was right!
I started to "scrutinise" it sound wise, over varying speeds and road surfaces and concluded that the car, given it's a diesel, is indeed quiet up to 65 mph, whereby low volume radio is perfectly audible. At 70 thro 75 it is distinctly louder exhaust wise, obviously with increased tyre and wind noise.
Anyone else notice any similar observations?

Thanks
Roger

 

[Sp!ke]

You said it gets quieter around 85 though yes?

Those clever Germans have probably figured thats the speed the majority cruise at and have tweaked out the noises for that particular speed.

 

[evdok]

Is it an OEM exhaust? third party systems tend to have a boomy affect. (experience from previous cars)

 

[hawk20]

If you read the road tests, they measure the sound levl accurately and Merecedes come out quieter than most as you would expect. And they are quieter at 70 than at 80 or 90 etc. Either you have a fault, or a non-standard part, or you suffer an audio illusion.

Just worth noting just how much the sound level varies with the road surface. Near Southampton on the M27, there is a tarmac stretch that is super quiet, and another that is very noisy.

 

[hawk20]

Large wheels with low profile tyres can also be noisy.

 

[Ian B Walker]

Or maybe there is a leak from the exhaust ?

 

[esox]

Just worth noting just how much the sound level varies with the road surface. Near Southampton on the M27, there is a tarmac stretch that is super quiet, and another that is very noisy.

Yes,it`s lovely that small stretch of surface,isn`t it?

Unfortunatly,i think the quality of road (and ammount of road noise)should never be an issue with cars that are supposedly at the prestige/refined end of the market.
If they are designed properly and have sufficient sound proofing it should`nt matter what the outside influences are - none should reach the cabin.It`s one of the reasons i sold my CLK.

BTW,in my experience Mercs get better at high(ish) cruising speeds...

 

[KLP 92]

You will suffer increased road noise due to it being an estate. The sound insulation isn't as good in the back of the car as you don't have an enclosed boot area which drowns the noise out from the rear wheels/exhaust.

I have owned several MB estates over the years, none are as quiet as their saloon versions.

 

[spitzkop]

Our C220 from New has had a boom effect around 80mph, a few mph either side and it disappears. Either going below or well above that speed, so never really let it bother me.