Buzzing sound, speed related

[Chisel86]

My '99 230 has been developing a buzzing sound from the front end that increases pitch as I go faster. It sounds a little like a big chunky truck tire as it rolls, but not as loud.
I have ruled out the tires though because it is the same when I swap the tires side to side and even when I had a different set of tires. It seems to get momentarily louder when the suspension unloads after going over a bump or a crest in the road.
I have also checked the wheel bearings for wear and play and found neither.

Anyone have a similar issue? Thanks.

[Vetruck]

Only thing I can think off hand is something aerodynamic. For instance did you change the antenna? Or maybe a fender liner or other plastic catching wind.

[Chisel86]

Hmm... It has no external antenna. It's the one in the rear glass I think. I'll have to inspect the plastic bits under the front end. It doesn't sound like something catching the wind because it is very consistent and I can hear it at low speeds too, like pulling up to a stop. I'll report back after some inspection.

[Denlasoul]

Check the little plastic piece that covers the fuel filter. Also check the plastic lining of the fenders.

[Chisel86]

Got a response on BenzWorld:

It is probably the insulation rubbing against the front driveshaft flex disc. The sound really seems to come from around the gearshift / cup holder area and is speed related. It seems to be a common problem with these cars when they install the insulation improperly and it touches the driveline. Go underneath the car, look at the driveline and if you see any clean shiny areas on the shaft, yoke, flex disc, etc., check the insulation above it. Once you found the area(s) cut away the insulation.


This sounds like a much more possible cause to what I was trying to describe. I'm gonna check it out this weekend and report on my findings. Thanks guys.

[Chisel86]

Found and fixed the issue! It was indeed the tunnel insulation that had fallen down and was rubbing on my front flex plate joint and drive shaft. There is a nice clean and shiny area where it had been in contact.

On another note, I had been meaning to check the condition of my flex plates and it appears that the front one is due for replacement. It never hurts to inspect things once in a while!

[Vetruck]

Congrates on the find. Glad it was not serious in any way, just annoying...lol

[Chisel86]

Yeah that was my fear, that some part of my drivetrain was slowly grinding itself away, lol