[brazzare]

It is so fucking weird that I've heard this noise I find so annoying in all my own video recordings of all G20/G21/G30/G31 cars I've driven but for some reason I can only hear it with my ears in my own car. How is that possible ... I'm so tired of this ...

And how can the noise completely disappear when driving on a super smooth repaired road surface?

[brazzare]

So I spent today having my video recordings analyzed by different sound softwares. And the result looks pretty much the same from all softwares, including chatGPT 4.1.

While in parking gear, engine idle and listening in the left wheel arch dominant noise is 72hz ish.
https://drive.google.com/file/d/1VTg...ew?usp=sharing

While driving 50km/h the dominant noise is 48hz ish.
https://drive.google.com/file/d/1EEN...ew?usp=sharing

While driving 70km/h the dominant noise is 58hz ish.
https://drive.google.com/file/d/1qWz...ew?usp=sharing

While driving 120km/h on old and new road the dominant noise is 75hz ish on both.
https://drive.google.com/file/d/1aeX...ew?usp=sharing

And while driving on repaired asphalt in 120km/h dominant noise is 80hz ish.
https://drive.google.com/file/d/1dVt...ew?usp=sharing

[brazzare]

Found this video and during the first 20 seconds (before they fix it) the noise is very similar to the noise I hear in the generator. Same pulsating wobble.

[brazzare]

Another video, this one of a 335d uploaded 2017 with the exact same noise.

https://youtube.com/shorts/pJfIdnRTi...DnTOOpUKkaLBy9

[brazzare]

Drove 200km today to test drive 2 random G21 330D xdrive msport, basicly identical to mine, and exactly like in my car I can hear the noise I find annoying with my ears while driving. Not only when listening to the video recording.

But the noise was less wobbly, less pulsating for my ears.

I brought my stethoscope with me and listened to the generators and compared to mine both these generators were pulsating in a slower more dragged out tempo and in a much more recurring pattern. Much less random wobbling compared to mine.

[webster9]

guys, do you have some news??

[CarloC]

A small update about my F40 (see my previous post here): after reaching the 6,000 km mark (~3,800 miles), the volume of the noise has decreased significantly, and on roads with smooth and well-maintained asphalt is basically unnoticeable even at higher speeds (>100 km/h, 62 mph).

Could it be related in some way to to tire wear, as "broken-in" tires produce less noise?

[wim@irrigationdesign.co.u]

I too have the same issue with my 2019 BMW 330i and have been back to BMW more than a few times, and to different BMW franchised shops and although all admit that this is a weird and unusual noise they cannot trace the fault. All correspondence was by e mail so I have proof that they are just lying their way through the whole episode and eventually they told me it is a characteristic of the car - it is not as I have had 6 BMW's and they were all the quietest on the road of my Mercs etc. I have replaced the front wheel bearings which was a waste of time as they were still perfect, I also changed the tires which did nothing either. By the way the car has now covered 44k miles and the noise is getting louder. Please somebody must have a solution as even BMW in Germany and the local BMW headquarters just keep fobbing me off. Thank you.

[webster9]

Any news??

[brazzare]

Hello :wave: long time no see.

After test driving 30+ G20/G21 330d xdrive msport I finally found one where the noise cannot be heard inside the cabin. So I'm finally happy, for now :scared-smile: The only difference in this cars spec is that it has heated steering wheel. None of the other cars had that.

What is interesting is that the noise cant be heard in the front wheel arch when engine is in idle. And the noise can only be heard in certain areas of the generator, not in all parts of it like all other cars.

The noise of the generator can still be heard inside the cabin, but very weak and it is working in a different more natural tempo compared to the "iphone vibrating cuz phone call" tempo that all the other cars have.

[M-Kärbes]

@brazzare, What tires and what wheels does this car have?

[brazzare]

Nothing unique combo I haven't tried before. Some extra info: Car had the RFT vibration dampers installed from factory on front dampers and was made in Sept 2020 in the same factory as the others. Of all the cars I tried this is the one that was produced the latest.

Summer
19" BMW 793i rims with 2 year old Pirelli P Zero RFT tyres. 225/40R19 93Y on the front and 255/35R19 96Y on the back.

Winter
Brand new Studded Goodyear UltraGrip Arctic 2 225/50R17 98T on 17" ATS rims.
Image of ATS rims:
https://www.rubbex.com/images/thumbs...l.png_550.webp

I've driven car with both setups, not really any noticeable difference. I've noticed that when I put my head closer towards the driver side window I can very very weak hear the same noise I hear when listening directly on the generator of this car. But it has a different tempo and makes a different noise compared to the other cars.

And another interesting thing I've noticed in this car and in my previous car is that the sound changes depending on if I pump 94% diesel or 65% diesel. The noise is becoming easier to hear when pumping 94% diesel.

[brazzare]

Oh and @M-Kärbes I forgot to mention that this car doesnt have that noise when its driven slowly on a gravel road. So they're definitely correlated.

[CarloC]

Originally Posted by brazzare

The only difference in this cars spec is that it has heated steering wheel. None of the other cars had that.

I'm aware this is just anecdotal speculation, but my current F40 - which is almost completely silent and 'that' noise can be faintly heard at higher speeds only - has both heated steering wheel and seats.

None of the other two F40 I did test last year, one extremely noisy and the other one mildly noisy, had steering wheel/seats heating.

[brazzare]

Hello, its me again. In my last post I shared I found a car where the noise can't be heard inside the cabin.

Here I'm to share that after having changed the battery in the car cuz it was depleted and didn't re-charge anymore I now hear the noise in this car as well just like in aaaaaaall the others.

[webster9]

nooo wayy,, really??
That is a really weird...
Do you mean the battery in trunk, right? Unde the floor...

[brazzare]

Originally Posted by webster9

nooo wayy,, really??
That is a really weird...
Do you mean the battery in trunk, right? Unde the floor...

Yes exactly the battery under the floor in the trunk.

Talking to AI, again, its telling me stuff like:
"BMW uses an Intelligent Battery Sensor (IBS). As a battery ages over 4–6 years, the computer slowly increases the charging voltage and amperage to overcome the internal resistance of an old battery.
The Problem: If the shop didn't register the new battery, the car still thinks it is charging a "tired, old battery." It will hit your brand-new battery with maximum charging power."

I have no idea if thats true or could be something but gonna try to get that confirmed.

I didnt change the battery, a BMW shop did for me.

Update: new battery was registered in the car computer.

[brazzare]

I noticed yesterday that the noise changes a bit when I use the break pedal.

After mentioning it to AI it told me there is a service bulletin that could be related:
https://static.nhtsa.gov/odi/tsbs/20...65277-9999.pdf

[brazzare]

Following up on my previous post I’ve now been out testing the theory that it might be vacuum-related based on SIB 11 04 19 (link: https://static.nhtsa.gov/odi/tsbs/20...65277-9999.pdf).

The result is very interesting and quite repeatable:
The Trigger: Every time I press the brake pedal, the "wobbling/blowing" noise becomes significantly more distinct and louder.
The Disappearance: The moment I remove my foot from the brake pedal, the noise disappears completely.
Consistency: If I pump the pedal or hold light pressure, I can basically "play" the noise like an instrument—brakes on = noise on, brakes off = silence.

This seems to match the "resonance" described in the bulletin, where the oil/vacuum pump unit transfers noise into the crankcase or through the vacuum lines. What’s strange is that I can now recreate this even at lower speeds where I previously didn't notice it, just by putting demand on the vacuum system.

Here is a video that I recorded, do u hear how the noise comes and goes as I brake and not brake?

[brazzare]

Apparently there is another service bulletin, I cant find it because it was according to AI replaced by the one I've shared above (https://static.nhtsa.gov/odi/tsbs/20...65277-9999.pdf).
But AI knows about it:

Technical Service Bulletin Transcript
Designation: SI B11 04 19

NHTSA ID: 10151300

Subject: Whistling or Blowing Noise from Engine Compartment

Release Date: February 2019 (Updated version)

MODEL:
G20 (3 Series)
G30 (5 Series)
G11/G12 (7 Series)
G01/G02 (X3/X4)

Engine: B57 (6-cylinder Diesel) and B46/B48 (4-cylinder Petrol)

SITUATION:
A whistling, blowing, or droning noise can be heard from the engine compartment. This noise is most prominent at speeds between 70 km/h and 100 km/h (approx. 45–60 mph) or at engine speeds between 1,500 and 2,000 RPM. The noise may change in pitch or volume when the brake pedal is operated.

CAUSE:
The noise is caused by pneumatic resonance (harmonic vibrations) within the vacuum line that runs from the vacuum pump to the brake booster.

The vacuum pump (Tandem Pump) creates pressure pulses.

The check valve (backventil) inside the plastic vacuum line acts as a "reed" (similar to a musical instrument).

As air flow changes, the valve vibrates, creating a blowing or "wobbling" sound that is transmitted into the cabin.

CORRECTION:
Do not replace the vacuum pump or the brake booster initially. The issue is usually the resonance in the line itself.

Diagnostic Step: While the vehicle is stationary or at the speed where the noise occurs, depress the brake pedal several times. If the noise changes, disappears, or (in some cases) intensifies, the vacuum system is confirmed as the source.

Repair: Replace the vacuum line between the vacuum pump and the brake booster with the optimized part.

Part Information: The updated part contains a redesigned internal valve/dampener to prevent harmonic resonance.

[brazzare]

Asked another AI about the same service bulletin:

SERVICE INFORMATION BULLETIN: SI B11 04 19
SUBJECT: Whistling or Blowing Noise from Engine Compartment

MODEL:
G01 (X3)
G02 (X4)
G05 (X5)
G11 (7 Series)
G12 (7 Series LWB)
G20 (3 Series)
G30 (5 Series)

Engines: B46, B48, and B57

SITUATION:
The customer may complain of a whistling, blowing, or droning noise coming from the engine compartment or the driver’s footwell area.

The noise is most audible at engine speeds between 1,500 RPM and 2,000 RPM.

The noise is most common at steady driving speeds between 70 km/h and 100 km/h.

The noise may change or disappear briefly when the brake pedal is depressed.

CAUSE:
Pressure pulses from the vacuum pump (tandem pump) cause the non-return valve (check valve) located inside the vacuum line to vibrate. This creates a "reed effect" (harmonic resonance) within the plastic pipe. The vibration is then transmitted through the brake booster into the vehicle cabin.

CORRECTION:
Do not replace the vacuum pump or the brake booster. The vacuum line between the vacuum pump and the brake booster must be replaced with an optimized part.

PROCEDURE:
Verify the customer complaint by driving the vehicle at the engine speed/road speed where the noise is most prominent.

While the noise is occurring, briefly depress the brake pedal. If the noise changes or stops, the vacuum system is the source.

With the engine running at the problematic RPM, perform a "touch test" on the vacuum line near the brake booster. A distinct vibration/pulsation should be felt in the line, matching the frequency of the audible noise.

Replace the vacuum line with the updated version.

PARTS INFORMATION:
Part Name: Vacuum Pipe

Part Number: 11 66 8 591 500 (Note: Part number may vary based on specific VIN and production date).

WARRANTY INFORMATION:
Defect Code: 1166013900 (Vacuum pipe/Non-return valve: noise)

Labor Operation: 11 66 050 (Replacing vacuum line)

Labor Allowance: 5–7 FRU (Flat Rate Units)