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      12-23-2009, 01:23 PM   #1
TheGooch
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Strange high pitched sound

Hi Guys-

So I have this really strange sound that i cannot for the life of me pinpoint. It basically sounds like a high pitched frequency that is typically heard when lightly accelerating from a stop or when coasting between 10 to 30 mph. It will typically last a couple seconds and come and go. It's faint enough that if you have stereo on you won't hear it.

a couple other points:

It never happens when stopped
It happens regardless of stereo on
it happens regardless of ac or heater on or off

Anyone have this issue by chance?

Anyway its bugging the shat out of me!!! It's going to the dealer next Monday so hopefully they can figure it out....

other than that I absolutely love the car.


Cheers,

Mark
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      12-23-2009, 01:44 PM   #2
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i get it too. i think it has something to do with the turbos. im going to have it checked whenever it goes in for service.
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      12-23-2009, 05:37 PM   #3
baf3472
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I think what youre hearing is the "efficient dynamics". Behind your front kidney grill are two vents that open and close depending if the radiator needs cooling or not. Its supposed to reduce fuel consumption when they are closed. This is from BMW's website

Open to increased efficiency.
A constant airflow through the radiator increases air resistance and affects aerodynamics. Electrically controlled vents in front of the radiator open and close the cooling air inlets so that the vents are only opened if cooling air is required. When the vents are closed, air resistance is reduced, as is fuel consumption
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      12-24-2009, 12:47 PM   #4
TheGooch
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Quote:
Originally Posted by freshwhite335 View Post
i get it too. i think it has something to do with the turbos. im going to have it checked whenever it goes in for service.
Hi Fresh-

In my case I really don't think it has to do with the turbos. I'll keep you posted though to what my issues ends up being.

Cheers,

The Gooch
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      12-25-2009, 05:54 PM   #5
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Quote:
Originally Posted by baf3472 View Post
I think what youre hearing is the "efficient dynamics". Behind your front kidney grill are two vents that open and close depending if the radiator needs cooling or not. Its supposed to reduce fuel consumption when they are closed. This is from BMW's website

Open to increased efficiency.
A constant airflow through the radiator increases air resistance and affects aerodynamics. Electrically controlled vents in front of the radiator open and close the cooling air inlets so that the vents are only opened if cooling air is required. When the vents are closed, air resistance is reduced, as is fuel consumption
If memory serves me right, this function is only on the 740d and 740i but not on the 750 and 760 models. I had looked at all of these different features when the F01/F02 first where introduced and found it rather strange that the 750 did not have that feature, but I think it has something to do with the amount of heat the 4.4l TTV8 generates...

There are other features that where originally listed on the F01/F02 in regards to the efficient dynamics but they didn't make it onto the north American market!
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      12-26-2009, 01:28 PM   #6
baf3472
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Quote:
Originally Posted by xDrive50i View Post
If memory serves me right, this function is only on the 740d and 740i but not on the 750 and 760 models. I had looked at all of these different features when the F01/F02 first where introduced and found it rather strange that the 750 did not have that feature, but I think it has something to do with the amount of heat the 4.4l TTV8 generates...

There are other features that where originally listed on the F01/F02 in regards to the efficient dynamics but they didn't make it onto the north American market!
Im about 99.9 percent certain that we have. If you remember back to when you first get your car, the rear back window had the stickers for it.
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      12-26-2009, 03:49 PM   #7
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Im about 99.9 percent certain that we have. If you remember back to when you first get your car, the rear back window had the stickers for it.
When I picked up my car, there were no stickers on any windows
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      12-27-2009, 04:06 PM   #8
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Quote:
Originally Posted by baf3472 View Post
Im about 99.9 percent certain that we have. If you remember back to when you first get your car, the rear back window had the stickers for it.
1+
My car had those as well
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