Jason B

I have a sound like this on a 2010 c300. It's like a hissing/static sound above 30 mph and gets louder the faster you go. It sounds like its coming from the middle of the dash area. Braking doesn't effect it and I even put it in neutral at 50 mph and shut the engine and radio off while coasting and it's still there. Ideas???

Sportstick

What happens on different road surfaces, such as asphalt vs concrete? The apparent direction of the sound can be very misleading. Our MB tech uses a directional stethoscope to find noises, as one cannot rely on what seems to be the source unassisted.

Jason B

Surface doesn't matter. Tar back roads, or concrete highway. It's like a tv on a white channel with no picture type sound.

dgghostkilla

yeah man send it to the dealer. let them find that ****. use the warranty while you have it

Jason B

Yea, was justr wondering what it could be. Will try to get it in next week.

Where is PA are you? So am I. Also, noticed the fan settings, when it's around the 4th or 5th bar for fan speed, it sounds a little whistlely, very slight, barely noticeable. Didn't know if that is normal. .

dgghostkilla

I live in montgomery county. Harlysville to be exact

qaz393

does it happen at idle? sounds like the brake booster leaking problem i have....

Jason B

Not at idle. I say 30 mph and above. It's like a "shhhhhhhh" sound

Sportstick

Have you manually cycled the climate control into different modes while it is happening to detect any possible effect?

Jason B

Yes and I have it "off" when I've been listening to try and figure out what it is..... Hmm. I'm going to try and get to the dealer soon.

Jason B

Just a little update, brought to dealer to have shop foreman ride along and we found if you open the ashtray, the hissing noise is much louder. So it seems to be coming from under. Car can't go in until next week. Any other ideas?