Vihzel

For any potential buyers, make sure you ask if the dealership will allow you to test drive the vehicle on the freeway to do a quick test to see if you can hear any glaring excessive wind noise or not. It would be the smartest thing to do so you lessen your chances at ending up with a faulty car.

I've been speaking with numerous dealerships around SoCal and have gotten some responses saying no, but others saying that it's fine. Don't just follow their prescribed test drive course either. I'll start test driving either tomorrow or Thursday after I get the pricing all settled. If I find that the cars I test drove had excessive wind noise, then at least I have a backup family car that I could use while I continue my search for a car.

Carsy

Good thinking.

Before you pay for your car on the day you pick it up ,take it for a highway run to check wind noise.

People on this site say vehicles some have wind noise, others do not.

MASSC450

A test drive on the freeway is in store before I pickup my new C300 next week!

kellens

Great idea! Some have noise right off the bat, and some develop it after a few hot/cold swings which leads the issue to be probably related to rubber seals somewhere.

You also have to get a day with some crosswind. Good luck!

Vihzel

Yeah I'm really hoping that the one I test drive doesn't have any wind noise or just has a little bit of it to where it's not bothersome, especially with music playing. I doubt I'd be able to get in crosswind conditions due to the location of the freeways, but I'll have to keep my fingers crossed on that.

LateC300

same, picking mine up saturday morning, but going to test drive the hell out of it beforehand. i have a nice checklist of things to look for

BrianC6H6

I followed OPs good advice when picking up my C300 this week. I took it for a spin on Route 101 with my sales guy in the back seat and my wife in the passenger seat. Here's what happened:
Me on on-ramp: "Nice and smooth acceleration."
Me merging into traffic at 50mph: "No wind noise. Great!"
Me accelerating in HOV lane: "Honey do you hear that? Is that wind noise?"
Honey: "Sounds ok to me."
Sales guy: "You're going 80mph!"

I'm ok with some wind noise at that speed.

So glad the car is sitting in my garage now. I really hope the car and I have a long and happy relationship.

LateC300

good, i hope that's my experience as well. crossing fingers and some other things

Vihzel

So I got back from the dealership and have a new C300. The one I have has some wind noise, but definitely not enough for me to not take the deal. I couldn't really tell how much of it was excessive wind noise and how much was normal wind noise, which may be a good thing. My G37 coupe had around the same levels of wind noise I think, but I can't really remember for sure since it's been years since I last drove that. I hope that overtime, I will even forget about the wind noise on a daily basis.

ManiacGT

I think I'd have been the same.

BlackjackM

Same here, daily commute of over 40 miles each way with lots of time over 80 mph and no noise that I consider to be bothersome, particularly with the radio on.

Steve71

I took a demo C300 out today to listen for wind noise. And I tried to compare it to my current car, a 2008 Audi A3. I don't have a proper sound level meter, but I used an app on my phone for comparison purposes. There was a cross wind of about 20 km/h today. Here's what I found:

A3 (my current car)
- Outbound at 120 km/h the sound level showed about 72 to 75 db. Very slight buffeting due to wind.. hardly noticeable and certainly not a problem. Sightly higher (maybe 73 to 75 db) sound level at 130km/h. Outbound here is slightly up hill.

- Inbound at 120km/h sound levels were slightly lower, (70 to 72 db), but I could hear the wind a bit more. I think I was heading slightly more into the wind coming back. I also believe the engine noise was slightly lower as I was coming down hill. I think that may explain why the sound level is slightly lower. To be honest, I'd say the sound level was about the same both ways, with a bit of buffeting both ways due to the cross wind.

Mercedes C300 4Matic (steel suspension, 17 in wheels, Comfort mode)
- Outbound and inbound the sound level metre bounced between 67 and 70 db. I'd say the eyeballed average was about 68 db. Very slight buffeting sound due to the cross wind at 120 km/h. Slightly more buffeting at 140km/hr, but nothing to be concerned about. Buffeting seemed slightly less than in the A3. Overall, the sound seemed more muted... possibly because it was quieter (decibel readings were lower) and partly because the sound that got through seemed to be at a lower frequency in the C300 (which is less noticeable to me). If I had the radio on, I probably wouldn't have heard the buffeting at all. And there was certainly nothing like a flapping sound reported by some owners.

As my car isn't being delivered until late September or early October, all I was doing here was establishing a base line with the dealer (the salesman was with me), so that if my car has a problem, we'll be able to agree that some cars do not have the flapping sound. I'll bring my phone (with the same app) for comparison purposes. If it's as good as today's drive, I'll be happy. If it's noisier, I'll have a baseline that they (at least my sales guy) has witnessed.

P.S. I attribute most of the sound level to road noise coming up through the tires.

cdahl383

My C300 is one of the quietest cars on the freeway I've ever had, almost zero wind noise. Wasn't aware some of these cars had an issue.

webcontrol

I have 2019 GLC 300, it is noisy with wind noise when speed over 45 mph. Dealer replaced door seals, with no help.

GreekUPS

Ask for the acoustic glass next.

jlr82

I've driven C300's with and without the acoustic glass and honestly I cannot discern a noticeable difference. Some people really notice it though.