Guess that mystery noise..

[fzootb]

Trying to work out this humming/droning noise in my new to me 35iS (yes, it’s an orange one).

Mileage - 78kish. Tyres are Continental sport contact 7 non run flat.

Noise/symptoms:

- happens/noticeable over 20mph. Changes pitch with wheel speed, no change from gear choice, rpm, neutral etc. does not change volume depending on speed, only pitch.

- No noticeable vibration when driving. No issues with brakes, no noticeable wheel creaks when cornering either side. Does not appear to be a single side but most likely driver’s side.

https://youtube.com/shorts/BOM1BPhhlDM?si=Qou-OyLGHlJ37nBN - here’s a short snippet of sound recorded by passenger but on driver’s side.

Doesn’t seem to whine in a way that would suggest diff, tyres are all correctly inflated, but welcome to anyone who has seen/heard of anything similar before I go down the route of potential fixes/diagnoses?

 

[B21]

Not sure what I’m listening for /too?

 

[fzootb]

Not sure what I’m listening for /too?

The noise that sounds like a light aircraft/buzzing noise that goes up and down in pitch as I accelerate.

 

[B21]

Not sure what I’m listening for /too?

The noise that sounds like a light aircraft/buzzing noise that goes up and down in pitch as I accelerate.

Nope can’t pick it out..could be anything ..

 

[ARCS]

Wheel bearing?

 

[john-e89]

Binding caliper, wheel bearing or possible dry driveshaft from what I can make out, it’s not very clear but that’s where I’d be starting.

Hope you find it.

 

[john-e89]

Binding caliper, wheel bearing or possible dry driveshaft from what I can make out, it’s not very clear but that’s where I’d be starting. Is either of the rear wheels hotter than the other after a run..?

Hope you find it.

 

[brillomaster]

My guess is wheel bearing. Though a few years back I thought I had a bad wheel bearing and it turned out to be the diff.

Either way, if you don't know when the diff fluid was last changed, I'd get that done at the next service. Cos if I didn't find a secondhand replacement diff, a new one from bmw would have been very expensive.

 

[B21]

If it was a wheel bearing you’d expect some change in tone during hard cornering ?

 

[Jollygiant]

If it was a wheel bearing you’d expect some change in tone during hard cornering ?

This, if it was bearing or part of the drive train it would change pitch/ volume at different speed, cornering pressure.

I've guessing something vibrating, undertray, a bit of trim somewhere, roof not fully up/down etc.

 

[Zed Baron]

Here's my guess (and only a guess)... does it come and go depending on how much fuel is in the tank

 

[B21]

If it was a wheel bearing you’d expect some change in tone during hard cornering ?

This, if it was bearing or part of the drive train it would change pitch/ volume at different speed, cornering pressure.

I've guessing something vibrating, undertray, a bit of trim somewhere, roof not fully up/down etc.

Also under hard braking in a straight line usually the extra loads effect the wheel bearing failure sound.. :tumbleweed:

 

[john-e89]

If it was a wheel bearing you’d expect some change in tone during hard cornering ?

This, if it was bearing or part of the drive train it would change pitch/ volume at different speed, cornering pressure.

I've guessing something vibrating, undertray, a bit of trim somewhere, roof not fully up/down etc.

Also under hard braking in a straight line usually the extra loads effect the wheel bearing failure sound.. :tumbleweed:

Not necessarily, remember on the video clip it’s very hard to hear anything out of the ordinary so if it is wheel bearing and it’s only just started being heard it’s in its very early stages so cornering and braking don’t have much impact until the bearing has worn more.

 

[B21]

This, if it was bearing or part of the drive train it would change pitch/ volume at different speed, cornering pressure.

I've guessing something vibrating, undertray, a bit of trim somewhere, roof not fully up/down etc.

Also under hard braking in a straight line usually the extra loads effect the wheel bearing failure sound.. :tumbleweed:

Not necessarily, remember on the video clip it’s very hard to hear anything out of the ordinary so if it is wheel bearing and it’s only just started being heard it’s in its very early stages so cornering and braking don’t have much impact until the bearing has worn more.

On mine there was no noise but if you dragged the brakes on left hand bends there was very light brake squeal only in certain circumstances..at MOT time they detected fractional tolerance in the left hand bearing ..

 

[john-e89]

Also under hard braking in a straight line usually the extra loads effect the wheel bearing failure sound.. :tumbleweed:

Not necessarily, remember on the video clip it’s very hard to hear anything out of the ordinary so if it is wheel bearing and it’s only just started being heard it’s in its very early stages so cornering and braking don’t have much impact until the bearing has worn more.

On mine there was no noise but if you dragged the brakes on left hand bends there was very light brake squeal only in certain circumstances..at MOT time they detected fractional tolerance in the left hand bearing ..

If the rear isn’t making noise under acceleration on a rear wheel drive car bearing then braking in a straight line won’t either.

Anyway my guess is a bearing has only just started to fail but obvs I could be wrong.

 

[B21]

Not necessarily, remember on the video clip it’s very hard to hear anything out of the ordinary so if it is wheel bearing and it’s only just started being heard it’s in its very early stages so cornering and braking don’t have much impact until the bearing has worn more.

On mine there was no noise but if you dragged the brakes on left hand bends there was very light brake squeal only in certain circumstances..at MOT time they detected fractional tolerance in the left hand bearing ..

If the rear isn’t making noise under acceleration on a rear wheel drive car bearing then braking in a straight line won’t either.

Anyway my guess is a bearing has only just started to fail but obvs I could be wrong.

I was looking at the reverse logic..does the noise change when the brakes are applied..given the floating caliper the caliper will tend to pull the wheel across the bearing,,that MAY alter the sound..I’m not suggesting it’s a guaranteed or unique qualifier…just one of many possible tests

 

[javis20]

Could also be a pulled cord in one of the tires. Other thought would be wheel bearing. If it's one wheel bearing, you can tell when cornering. I had a Jetta with both front wheel bearing bad. Could not tell when cornering.

 

[firebobby]

Could also be a pulled cord in one of the tires.

Worth checking the tyre's, I had a humming/wer wer sound from the rear of my car.
I wondered if it could be brakes/ bearing/ diff, but it turned out to be one of the tyre's had lost its shape.
They don't last like they used to.

 

[fzootb]

It was wheel bearing. No change going around corners. Had a check with Birds.