Major Vibration from Sunroof It Seems - Anyone Else?

[Bmore]

i've had my car for a few months now with no issue with the sunroof all the while, except maybe that the wind noise is more than i would like. anyway, i was driving earlier in the week and had the sunroof open and all of a sudden upon takeoff there was a loud loud loud vibration noise (super loud and so much so that i was wondering if the whole car was vibrating or if my wheels were flat or what was up) which i felt like was stemming from the sunroof being open. the noise/vibration (more a vibration with noise) only happens at slow speeds and disappears at 45mph and above. it's so intrusive that i have to take it to the dealer soon. i waited and it has done the same thing every day this week.

the sunroof looks normal and i don't see anything off or out of place or which could cause the issue, so i'm dumfounded.

anyone else?

[dividedhighw]

Hmm - this may not be your problem, but on my sunroof, the deflector that normally pops up when open was not deploying properly and that led to some extreme wind buffetting in the car.

Once I forced it up manually, the problem went away, so I had the dealer lubricate the spring-loaded deflector. I had the problem once more since then but I'm hoping with the warmer weather, it'll get exercised more and allow the lubrication to work in everywhere before long.

HTH,David

[bosh]

Yes, I had that same problem - with my winter tire setup - I thought my eardrums were going pop , at any speed - solution - open rear window just a crack...or switch back to summer tires.

[cjre1]

Funny, I heard of this problem. Some say it is caused by the tires and some say it is the sunroof deflector. Strange, because they are unrelated.

[Bmore]

I now realized that this happens when my back windows are cracked at a certain level (not at all levels). The noise kills your ears and feels like the car is going to rocket off into space it is vibrating so much. I had a passenger in the car and said hey can you notice this and she was like "Owwwww! Stop it!" because it really does hurt your ears and sound so loud. Very crazy. Not acceptable at all. What on earth could it be?? Some sort of weird wind tunnel effect?

[Bmore]

I don't think it's the tires. I think it is some sort of wind tunnel effect.

Interestingly, the "vibration" that comes along with the sunroof stops when I get to speeds over 45mph. But the "vibration" that comes with the back windows cracked starts when I get to higher speeds.

Ouch. The noise is SOOOOOOOO loud, like a rocket ship. No way anyone can drive the car like that. You're forced not to use the sunroof or windows.

[cjre1]

What about having wind deflectors installed? Does this help?

[Bmore]

Don't think it could help if it is also caused by just the back windows being open and sunroof closed. I'm going to take it to the dealer and see what they say. Hopefully it won't mysteriously disappear/not occur when I go on a ride with the service person.

[cjre1]

Let us know what the dealer says. This has to be the aero-dynamics of the car. What about addding those window deflectors to the car. I know that it will look dumb.

[MALEX]

I've had similar problems with other vehicles - open the front/rear windows and/or the sunroof a certain way and the interior of the car seems to start pulsating and it feels like your ears are going to explode - wumpwumpwumpwump.... I think air coming into the passenger compartment at a certain speed sets up some kind of resonance, with the passenger compartment being the resonator cavity - after all the frequency is quite low, maybe a few Hz. In one car I had the roof would start pulsating - it was like being inside a bass drum.

It usually happens with the EX when the front windows are open just right at certain speeds. Crack the rear window, and it goes away - maybe.

Never had the problem with my ancient vehicles - only cars built after about 1997. I just assumed it was because newer vehicles were being made with lighter, more flexible materials.... maybe something to do with unibody construction? There is probably a PhD thesis out there on the topic....

Cheers -M

[MALEX]

Here is what I got when I Googled on interior noise in cars:

Analysis of Vehicle Wind Throb Using Cfd and Flow Visualization

Date Published: February 1997

Author(s):Tetsuji Ukita - Mitsubishi Motors Corp.Hiroshi China - Mitsubishi Motors Corp.Keisuke Kanie - Mitsubishi Motors Corp.

Abstract:Passenger cars with sunroofs sometimes experience a low frequency noise called "wind throb" when traveling with the roof open. This "wind throb" should be suppressed because it is an unpleasant noise which can adversely affect the acoustic environment inside a car.

[cjre1]

Maybe this is caused by the aero dynamics of the car. These new cars are very rounded now.

[dividedhighw]

Never had the problem with my ancient vehicles - only cars built after about 1997.

Sorry, but that's not my experience. I've had a moonroof on a number of vehicles prior to 1997, including:1982 Olds Cutlass Supreme1986 Merkur XR4Ti1988 Volvo 740 Turbo1990 Audi Quattro 901992 VW Passat Syncro Wagon1993 Audi S4

All had the same symptom at different speeds with different configurations (which windows open, how far, etc). One thing common in all cases was that a front-mounted deflector minimized or eliminated the number of situations in which the "wind thump" symptom arose. Some of the above-noted vehicles had one built-in while on the others I had to add an aftermarket one.

As you suggested, it's caused by resonance (constructive interference), so it's a matter of mathematics (based on speed, airflow, passenger space capacity, etc) which varies by car.

As I already posted, when the built-in deflector on my EX wasn't popping up as it should, I had this symptom. Otherwise, it hardly happens - but, when it does, cracking one of the rear windows has ALWAYS cured it.

HTH,David