Whistle sound before switching gear

[zerrantoss]

I have a N55 engine. When the car starts moving from stationary, just before the first gear switch (around 2000 RPM), I can always hear a slight whistling sound coming from the front.

This happens only in D mode. I tried to use M and navigated around this RPM range in the 1st and 2nd gear, no whistling sound at all.

I am wondering if this is normal. Does any other N55 owners have the same issue? Should I take it to the dealers (I bet they would just say it's perfectly normal).

[Ultimas]

Could it be the Turbo Spooling up?

[bak]

I just started hearing the same thing on my 09 X6 35i. I am scheduled to go to dealer next Tuesday for another issue and will see what they say. Sounds like its transmission or gearbox related to me since it seems to occur during shifting at low speed.

[zerrantoss]

Thanks for the replies.

Ultimas: If it's turbo spooling up, should also happen to the other gears as well? I can only hear it before the first shift..

bak: If it's transmission/gearbox related, is it possible for it to happen only in D mode? My Sports and Manual mode seems fine without the sound.

Anyone else have the same problem? Or any engine experts out there that might know what could be the cause?

[dmlgc]

I hear gear whine when trans is in sport mode( all gears) but not a whistle sound.
Would be interesting to hear what the dealer has to say.

[zerrantoss]

Okay, I will drop by some time this week to the dealer, and let you guys know what kind of story they can come up with

[bak]

Here is an update on my visit with the dealer. I had an appointment to get the X6 in for another problem yesterday......I asked the service manager if he would take a ride and he got a technician to go with me. The tech heard the sound and he thought it was engine related as opposed to transmission. We tried to duplicate the sound in neutral with no luck. He said there was no doubt he heard the sound and he thought it was either a vacuum line or possibly a turbo leak. He was going to put the car on the hoist and run it. Service advisor called yesterday afternoon and said they found a leaking hose, I asked which one and he did not know. They were having one overnighted and will install it today and then check to see if the noise goes away. I will let you know if it solved the problem and if so what hose it was.

[zerrantoss]

Originally Posted by bak

Here is an update on my visit with the dealer. I had an appointment to get the X6 in for another problem yesterday......I asked the service manager if he would take a ride and he got a technician to go with me. The tech heard the sound and he thought it was engine related as opposed to transmission. We tried to duplicate the sound in neutral with no luck. He said there was no doubt he heard the sound and he thought it was either a vacuum line or possibly a turbo leak. He was going to put the car on the hoist and run it. Service advisor called yesterday afternoon and said they found a leaking hose, I asked which one and he did not know. They were having one overnighted and will install it today and then check to see if the noise goes away. I will let you know if it solved the problem and if so what hose it was.

Thanks for the update Bak.
It is most likely that I have the same problem as you. It is fortune for you that the tech is actually admitting the problem, and worked on it efficiently.
Mine will probably just say: "It's what turbo sounds like! Perfectly normal! Live with it!".
I will keep you updated when I visit them.

[kumar911]

I have the same problem, I hear a the same noise kind of like a police siren if you may. This happens when ever I slow down.

[bak]

I picked up my car yesterday and was advised that the noise was normal for a turbo motor. When I asked why it just started at 50,000 miles I did not get an answer. The tech advised me that when the turbo makes pressure and then you let off on the gas this noise is caused by the pressure having no where to go. There was not much I could say so on my way home from the dealer I left the radio off and noticed when I made a turn and accelerated the noise was very loud. So much for the tech's theory that it was upon de-acceleration that this is occuring. I am going to go out on a limb here and guess that the noise is coming from what ever it is that controls which wheel the power goes to. Something gearbox related. I just purchased the best extended warranty so there is really no urgency to get this fixed, I will wait till it gets worse and then take the service manager for a ride. I will follow this thread and if anyone comes up with a fix please post. Sorry for the disappointing news I hoped to be more informative. Best, Brian

[zerrantoss]

Originally Posted by bak

I picked up my car yesterday and was advised that the noise was normal for a turbo motor. When I asked why it just started at 50,000 miles I did not get an answer. The tech advised me that when the turbo makes pressure and then you let off on the gas this noise is caused by the pressure having no where to go. There was not much I could say so on my way home from the dealer I left the radio off and noticed when I made a turn and accelerated the noise was very loud. So much for the tech's theory that it was upon de-acceleration that this is occuring. I am going to go out on a limb here and guess that the noise is coming from what ever it is that controls which wheel the power goes to. Something gearbox related. I just purchased the best extended warranty so there is really no urgency to get this fixed, I will wait till it gets worse and then take the service manager for a ride. I will follow this thread and if anyone comes up with a fix please post. Sorry for the disappointing news I hoped to be more informative. Best, Brian

Hi Brian, sorry to hear that they did not come up with a solution.
I called my dealer yesterday. They booked me in on 11th (next Tuesday). I will update what he has to say.

The sound is not really a sharp "whistle" noise. It is like a combination of whistle + some friction due to rubbing + faint sky train / subway driven by noise.

[zerrantoss]

I went to the dealer yesterday. They said it sounds like something is loose. I really doubt it because the whistling sound goes away above 3000 rpm.
They will take it in next week for a full inspection.

[zerrantoss]

So after a month of inspection, they have found no solution...

In the beginning they told me that something is definitely wrong, and that they will find out what's wrong.

After a few weeks, they found out that the hissing noise disappears if they unplug the waste gate valve controller. So the problem should be somewhere around that area.

Today, they are telling me that they don't know how to fix it. They see the same problem on other N55 X6s as well. BMW is aware of the issue, and they have no solutions for it.

Does anyone else with N55 engine have the same issue? The dealer told me that it happens in other X6 as well, but I think it is just an excuse to get themselves off the hook.

This is very disappointing, especially on a $80k 2011 car.

[gabrielglg]

I have x6 35 i and same problem...I made all updates posible on dealer, I changed bouth's turbo and all exhaust sistem, vacum hoses and the sound is steel here.
Anyone has somethyng ney about this?
My car is '08, updates made of this car are the latest.
I put back the factory softwere and the sound is steel there.

[gabrielglg]

No one ?
I guess i will buy a new engine and i will see if the problem disaper...

[aacabriolet]

Have you changed the sound in the car at all? I know there is a high pitched whine that is caused by some crap hi-lo converters..

I know, may sound stupid but you never know so thought i would mention

[gabrielglg]

They are new...Yesterday i have changed again all injectors and fuel pump frm engine and no result, I wait for 2 days a new map sensor and i will see what happens.
Any ideeas ?

[gabrielglg]

I have just changed 2 custom soft on the engine and nothing changed.
What should i do ?
I have anything new on the engine .
turbos, catalizator,fuel pump, spark, spark plugs, all [pipes, oil filters,all sensors..., the car wisle when take the foot on the gas.

[zerrantoss]

i thought the sound would go away when the temperature is warmer. Now it's summer, and the problem is still there.

Now I can only turn up the music, and ignore the hissing noise

[bak]

Here is a update to this thread......I went pretty much all summer long without hearing the noise and then recently the noise was very loud. It happens mainly under acceleration and now there is a definate loss of power. Sometimes it is constant and sounds like a siren. If you continue to press the accelerator during this time and the trans downshifts the noise stops and the car accelerates normally. I scheduled the car for service Wed 9/14 and insisted that the service manager take a ride. He could not believe the noise that was coming from the car, he said, "That's a new one" He assured me he would get to the bottom of it. On Thursday I received a call and they said the Catalitec Converter had come apart and was causing a intermtten blockage in the exhaust. They had to order one from Germany and it won't be here till next week. I will update when I have more to share.

[aacabriolet]

Originally Posted by bak

Here is a update to this thread......I went pretty much all summer long without hearing the noise and then recently the noise was very loud. It happens mainly under acceleration and now there is a definate loss of power. Sometimes it is constant and sounds like a siren. If you continue to press the accelerator during this time and the trans downshifts the noise stops and the car accelerates normally. I scheduled the car for service Wed 9/14 and insisted that the service manager take a ride. He could not believe the noise that was coming from the car, he said, "That's a new one" He assured me he would get to the bottom of it. On Thursday I received a call and they said the Catalitec Converter had come apart and was causing a intermtten blockage in the exhaust. They had to order one from Germany and it won't be here till next week. I will update when I have more to share.

bleh, you don't need the stupid cat anyways

[zerrantoss]

Originally Posted by bak

Here is a update to this thread......I went pretty much all summer long without hearing the noise and then recently the noise was very loud. It happens mainly under acceleration and now there is a definate loss of power. Sometimes it is constant and sounds like a siren. If you continue to press the accelerator during this time and the trans downshifts the noise stops and the car accelerates normally. I scheduled the car for service Wed 9/14 and insisted that the service manager take a ride. He could not believe the noise that was coming from the car, he said, "That's a new one" He assured me he would get to the bottom of it. On Thursday I received a call and they said the Catalitec Converter had come apart and was causing a intermtten blockage in the exhaust. They had to order one from Germany and it won't be here till next week. I will update when I have more to share.

Thanks for the update.

The last time I went to the dealer, they unplugged some sort of plug on the turbo unit, and the sound disappeared, so they were certain that it was some part of the turbo causing this issue.

But at the end, they still haven't solved the issue.