[SlimSjakie]

Good morning,

I have noticed a humming sound (low frequency) accompanied by vibration since last month when driving above 140 km/h in my BMW G30 540i XDrive. This only when I demand power from the engine, when I release the throttle both the noise and vibration are immediately gone.

Went to the bmw dealer yesterday, a mechanic there drove it for a bit, he says he also feels it slightly at speeds above 100 km/h already.

They suspect the front left driveshaft needs complete replacement, but can't say with 100% certainty that that will solve the problem. It could also be the cardan shaft from front to rear they say, which transmits the vibration and noise to the front. It seems to be coming from the front.

They suggest putting a similar car next to it, and then swap that front left driveshaft first to see if that solves the problem. If that doesn't solve it, then they want to swap the cardan shaft.

So all the labour that goes into this will be on my account. So also dismantling the part from the similar car, and reassembling it. So this is going to be a pretty expensive deal for me, and it's not even certain to stop here.

I wonder if there aren't better ways to tackle this problem. E.g. diagnose/localise the EXACT problem with the right measuring equipment so that the cause can be fixed in one go.

And then my 2nd question: this is a 2018 car with 47k kilometres driven, I am the 2nd owner bought in 2021 with 18k kilometres run. I drive it pretty quietly. How is it possible that a driveshaft needs to be replaced already?

Suggestions are welcome!

[choppedliver]

Drive shaft Guibo? I’ve just had mine replaced as I had vibrations for, 130+. Checked front wheel balance and for bends and they were fine. Dealer checked and said it was a driveshaft union. I’m guessing and will know later that it was the rear driveshaft/tailshadr guibo.

[SlimSjakie]

Originally Posted by choppedliver

Drive shaft Guibo? I’ve just had mine replaced as I had vibrations for, 130+. Checked front wheel balance and for bends and they were fine. Dealer checked and said it was a driveshaft union. I’m guessing and will know later that it was the rear driveshaft/tailshadr guibo.

hey choppedliver,

could you describe the vibrations you experienced at 130+? were they permanent or only when the engine has to work, did they stay after you let go of the gas pedal?

and what type of noise could you hear?

[oldtexasdog]

Best to have the center support bearing replaced at the same time. But chances are good it is what it sounds like.
Also as you usually have to remove much of the exhaust system to aceess it it might be a good time for a exhaust upgrade if you have been thinking about it.

[choppedliver]

Originally Posted by SlimSjakie

hey choppedliver,

could you describe the vibrations you experienced at 130+? were they permanent or only when the engine has to work, did they stay after you let go of the gas pedal?

and what type of noise could you hear?

Mine was a shaking in the front seats, worse on long left corners, not as bad on the right. Straight on it wasn’t too bad. I didn’t notice a difference on or off the gas.

[gasoline]

Originally Posted by SlimSjakie

Good morning,

I have noticed a humming sound (low frequency) accompanied by vibration since last month when driving above 140 km/h in my BMW G30 540i XDrive. This only when I demand power from the engine, when I release the throttle both the noise and vibration are immediately gone.

Went to the bmw dealer yesterday, a mechanic there drove it for a bit, he says he also feels it slightly at speeds above 100 km/h already.

They suspect the front left driveshaft needs complete replacement, but can't say with 100% certainty that that will solve the problem. It could also be the cardan shaft from front to rear they say, which transmits the vibration and noise to the front. It seems to be coming from the front.

They suggest putting a similar car next to it, and then swap that front left driveshaft first to see if that solves the problem. If that doesn't solve it, then they want to swap the cardan shaft.

So all the labour that goes into this will be on my account. So also dismantling the part from the similar car, and reassembling it. So this is going to be a pretty expensive deal for me, and it's not even certain to stop here.

I wonder if there aren't better ways to tackle this problem. E.g. diagnose/localise the EXACT problem with the right measuring equipment so that the cause can be fixed in one go.

And then my 2nd question: this is a 2018 car with 47k kilometres driven, I am the 2nd owner bought in 2021 with 18k kilometres run. I drive it pretty quietly. How is it possible that a driveshaft needs to be replaced already?

Suggestions are welcome!

Hey, is there any update about the issue?
What kind of a noise is it? I mean is it continuous or a pulsating one coming intermittently sounding like wooh wooh…a second?
I have an irritating noise searching for the cause, any update/idea is appreciated

[gasoline]

Originally Posted by choppedliver

Drive shaft Guibo? I’ve just had mine replaced as I had vibrations for, 130+. Checked front wheel balance and for bends and they were fine. Dealer checked and said it was a driveshaft union. I’m guessing and will know later that it was the rear driveshaft/tailshadr guibo.

Hey choppedliver,
What was the frequency of the vibration? Was it a pulsating (like 1 at a second) or continuously coming noise/vibration?

[oldtexasdog]

Kida rude when someone ask a question and you take the time to answer it then they just disappear?. Don't you think?

[gasoline]

Originally Posted by oldtexasdog

Kida rude when someone ask a question and you take the time to answer it then they just disappear?. Don't you think?

Exactly, so many threads were left like this

[gasoline]

Hi,
As I learned from the mechanics;
If the vibration or noise stops as you let off the gas pedal, it indicates that the problem is related to cv or u joints, or driveshaft in general. Because with the gas applied , these parts are loaded to rotate and any cracks on them will cause vibrations. If you release the gas no torque is applied to these parts, free to move during coasting, and no noise.

[SlimSjakie]

Sorry guys, i didnt' receive any notifications that there were questions about this, so I kinda left this post a bit. Also, i am still in progress with the issue, it has not been resolved yet.

The vibrations can be described as ' pulsating' and are mostly noticable when pushing the gaspedal in a little (say 15-20%) at higher speeds over 135km/h. When pressing at 50% or higher, accelerating to 170 km/h, the vibrations are less noticable. When letting the gaspedal go at higher speeds, the vibrations disappear.

My BMW dealer suspects it's one of the drive axles, but they are not sure which one.

I'm going to get it diagnosed at a garage that has NVH equipment, so they can pinpoint the exact part that is causing this.

[SlimSjakie]

p.s. is this forum not supposed to send out an automatic email notification if there are replies to a thread I've created? In my user CP i see there are no threads i am subscribed to, and i see no option to subscribe myself to this thread.

[gasoline]

Originally Posted by SlimSjakie

Sorry guys, i didnt' receive any notifications that there were questions about this, so I kinda left this post a bit. Also, i am still in progress with the issue, it has not been resolved yet.

The vibrations can be described as ' pulsating' and are mostly noticable when pushing the gaspedal in a little (say 15-20%) at higher speeds over 135km/h. When pressing at 50% or higher, accelerating to 170 km/h, the vibrations are less noticable. When letting the gaspedal go at higher speeds, the vibrations disappear.

My BMW dealer suspects it's one of the drive axles, but they are not sure which one.

I'm going to get it diagnosed at a garage that has NVH equipment, so they can pinpoint the exact part that is causing this.

Hi, thanks for the explanation.

I made a test with a vibration meas. app (not the NVH brand) and caught the frequencies of vibration at 120 km/h speed, very clearly. After the math calculations; I realized that these vibration frequncies exactly correspond to tire rotation speed and its 2. and 3. order harmonics.

So, first observation; my car’s vibration frequncies are not due to driveshaft or engine speed related, it is a tyre speed related one. Otherwise these frequencies would be a fraction of engine rpm or shaft rotation speed, but not. So, I got the first clue.

Second; the literature states; if only a typical tyre balance problem exists, it never creates 2nd or 3rd order vibration, it would create just the 1st order vibration, that is the tire rotation frequency. But I have 2nd and 3rd ones also.

If 2nd and 3rd orders exist, these are usually said to be indicators of a “radial force variation”, usually on tire edges at 2 or 3 points due to several reasons. So, the road force balance machine will catch these points and correction will be possible if lucky.

Many users also mention “wheel to hub centering problem” due to over tolerance difference between the hub and wheel bore diameter in some G30s, which may cause the wheel not be mounted at the exact center of the hub and not be following a perfect circular path, thus creating vibration.