xSky

Hi, I am a new owner of 2020 GLB 200. Really love how the car drives and those fancy tech features. Came from a Mazda CX-9 2021 top end model.

​​​​​​However I notice that the GLB isn't as soundproof like the Mazda is. I think it was around more 3-4 db when driving on the same road conditions.

The car tyre is a Continental Premium Contact 6 on 19inch wheels. Not sure if this tyre is causing most of the noise, or the car itself which lacks of sound insulation materials. (Previously running on 20inch wheels).

I drive 80% on rough contry roads. Would appreciate any advice to improve this. Thanks!!

benz_driver

IMHO the GLBs are noisy, I found the non-AMG model 250 (US) noisier than my 35. A friend has a 250, I recommended installing an under-hood pad - my 35 has one. She installed the pad, big difference in noise reduction. MB sells them online now via eBay or you can buy one now from a dealer - it's a non-standard item, IMO they will not install a pad. Don't forget the push clips! Here's the pad (eBay UK):
https://www.ebay.com/itm/284878135180
I'm planning on installing sound deadening in the rear deck and under the stowage panel. Drive around a bit with the rear seats folded down, you'll want to do the same. I don't think it's your tires - I drove a 250 for about a week on 19s and with the Off-Road Package, they were on par with the 20s on my 35.

xSky

Thanks mate appreciate your reply. I've asked my dealer if they have that item, hopefully they do have it. Good to know that it will make some difference. The Mazda also has that pad installed maybe that's why it was more quiet.

How easy is the installation? I don't work much with cars hopefully it's not too bad.

benz_driver

The pad did make a difference in her 250, the retrofit took her about 15 minutes given that she had the push clips. She told me that she almost gave me a call for help - I'm 6'7" and can reach the middle of the engine bay, but she managed without issue and, by her own measure, she's not mechanically inclined. The pad was perfectly fitted and lined up with the interior of the vehicle's bonnet (hood here in the US!).

I owned a US-spec 2011 Subaru Forester XT, a zippy version of that model, and it was seriously buzzy until I had the same padding done under the hood and in the rear deck. Do drive a few miles in your 200 with the seats down, you'll hear what I mean!! Cheers!

benz_driver

Almost forgot to add, that pad is standard on the GLB 35, don't know why MB cheaped out with the other models.

xSky

Thanks mate, will definitely try the padding first. For the clips, where do I get them? Cheers

benz_driver

MB sells the clips, they're about 75p/$1 each. I always buy a few extra, they're like circlips - I nickname them "Jesus Clips". They tend to spring out and are impossible to find then, hence the following "Jesus" exclamation…

xSky

The MB dealer still checking about the padding. They did mention that there is a potential fire hazard risk for GLB 250 and GLB 200, therefore they didn't fit it straight from the factory (only the 35 that comes with it). I'll update again once I hear from them.

xSky

Regarding the fire risk hazard according to MB dealer

Odd Piggy

If you have the MOE (run flat) tires they aren’t particularly quiet. Mine has Continental ProContac GX. The older base model GLB250 just doesn’t seem to have a lot of sound insulation. I would assume the GLB200 is about the same. Our 2021 was quieter than our 10 year old C250 until I replaced the motor & transmission mounts, took off the C250’s sport tires for all seasons, and reinstalled the torn up sound insulation over the axle tunnel in the trunk. The sound level in the C250 on an average highway at 60 MPH dropped from 75dB to 68dB, while the GLB250 registers 72dB on the same road.

What is interesting is that we have a 2023 GLA250 with identical equipment to the 2021 GLB and it is noticeably quieter. I also had a 2023 GLB250 loaner at my last service that was much quieter. Seems like the newer ones are better insulated. I can’t see any external difference between the GLA and the GLB engine compartment and underside. Neither one has a hood liner. I have to assume the difference is in the floor panel insulation. Insulation can be added by adding it under the carpet, but it’s quite a chore.

I would be interested in hearing what you do to address the noise.

Odd Piggy

The GLB35 also has a turbocharger. That reply doesn’t make sense to me.

xSky

Thanks for the feedback. Last time I run it I think it was around 73 db on that speed and rough road surface. I might take the car to a professional audio car shop to get the floor insulation installed. Will it affect the warranty?

Odd Piggy

I had not considered that. Our GLB250 is over 50,000 miles, so out of warranty. Benzes usually have CANBUS connections in the footwells, so it’s something to consider.

xSky

Ah that's a shame. So the only thing we can do probably to switch to something like a noise cancelling tyres? I did some research the tyres that we have now do around 72db. While grade A tyres do maybe 3 db less than that?

Odd Piggy

Not sure what grade A tires are. Is that a rating from your local government?

What I do know is that on my 2013 C250 adding insulation and repairing the damaged stuff in the trunk got me from 75 down to 72. Taking off the Yokohama V405 and putting on Michelin PSAS IV got me from 72 to 68. Tires can make a big difference if the car is inherently quiet.

I don’t know if we’ll ever get there on a 2020-21 GLB. They’re just more noisy. Stand out near the front when it’s idling. Lots of mechanical noises. The W204 didn’t have that to begin with.

Speculating here, but, I have read somewhere that the original GLB used plastic engine mounts and suspension dampers for durability. Then in 2022 when the GLA went to the 247 chassis both cars went back to rubber. ??? Maybe the plastic is passing more noise to the passenger compartment.

ILoveNY

wow good to learn about the pad

Vladimir Livson

I installed aftermarket insulation pad and kept it on for a year. After seeing xSky post I decided to check to see the condition of my pad. There was no discoloration from heat, however when I looked closer at the side over the turbo the pad deformed, it was twice as thick as the rest of the pad (expanded from original condition). So I took it off. I do agree with Odd Piggy, that in principal there should be no difference between GLB35 and GLB250 as both have turbo’s in the same spot, and since 35 has more horsepower I would imagine that turbo gets even more hotter. So I am wondering if my issue relates to not having OEM pad.

ILoveNY

is there a link to the OEM pad and non-OEM pad？

xSky

Thanks, I will update again once the tires need to be replaced. I will replace them with quieter tires.
The other day I installed a transparent rubber sealing on all doors and the boot. It was a nice surprise that the noise was reduced by a few db (initially I just wanted to prevent door dings and scratches). This could be a good workaround for now.

Vladimir Livson

​​​​​​
OEM part number is A 247 682 28 00
You can order it from a local dealer or online from veriety of shops. Below is one I found on Google.
https://www.shopmbpartsnow.com/oem-p...ood-2476822800

You can purchase aftermarket one from AliExpress. That is where I got mine.
https://www.aliexpress.us/item/32568...2usa4itemAdapt

benz_driver

Chiming in with a +1 a recommendation to mount different rubber, I have 20" Michelin PSAS4 mounted to BBS wheels. I own an '07 E550 Sport Package with 18" BBS wheels (square set) with Vredestein Quatrac Pro rubber mounted, the Vredesteins are far quieter than the previous Michelin PS3+ rubber - the newer tires are "all-weather" here in the US, grand touring category - they're pretty quiet and great for damp/wet weather and decent in dry weather. I'd offer considering a Vredestein or Michelin grand touring tire - look up Tyre Reviews on YouTube, the author is UK-based and pretty comprehensive in his reviews including subjective comfort and road noise.

I'm still planning on a trip to an auto stereo installer to add some sound deadening, something like Second Skin's acoustic mats.

I had a spirited drive today in poor weather conditions on rough roadways including some fun twisties. I do not use my Burmeister stereo, strange, I know. Upper 40s, made sure that I had my tires inflated before I headed out, up to 80 mph on an Interstate. I've made the same trip in my E550 albeit not corner carving as I did today in my GLB 35, but IMHO touring rubber and some well-placed sound deadening will leave your GLB much, much quieter. My 2¢.

kgzero

Interesting. I'll have to check out the dampener in my car.

tbirdvet

Most of the noise is not from the engine compartment. The GLB has less sound insulation in the body panels and does not use laminated glass like in some other models which keeps the cost down. I feel the tire noise is minimal.

MnewB22

GLB 35 Engine


GLB 250 Engine

Odd Piggy

I only see slight differences in the pictures, but I’m not going to go against a MB warning on a 2 year old car. I was going to fabricate one for my GLB250 from foil backed rock wool sound insulation. But my 2 indie mechanic acquaintances said only unbacked fiberglass was suitable. So mine I’d still uninsulated.