[toksis]

Hi,

I had bought a BMW imported from japan. It is a 2006 320i. I just notice that there is a weird sound rumbling sound. It is like a bass sound wob wob wob. Like a big boat when I run between 30 to 40 kilometers per hour. Is this a normal thing? I'm driving the car on a smooth road.

https://www.youtube.com/watch?v=rMOaDe6rcFI&feature=youtu.be

 

[wilt]

It could be low frequency rumble indicating wheel bearing(s) starting to go bad.

When you hear the rumble, try putting the car in neutral and letting engine RPM drop to idle, with the car continuing to roll, and see if the rumble continues in spite of transmission being out of gear and engine at idle. It is possible for a mechanic to put the car on a lift, rotate each wheel by hand and FEEL any roughness in a wheel bearing that is going bad. Two bad wheel bearings can set up a 'beat frequency' and make the wob-wob-wob effect. I once had a low frequency rumble at slow speeds during turns, and the dealer found I was right about wheel bearings in the process of going bad.

 

[dmatre]

More likely the tires are worn & feathered. I've had tires that were so loud that I've changed them with more than 1/2 tread left.




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[toksis]

I will update you guys. I will try to do a neutral when speed will be at 40kph. Thank you.

 

[toksis]

Hello guys,

I run the car now and then went to 40kph speed then set the Transmission to neutral. Rumbling is still their. What would be the problem?

 

[CALWATERBOY DUE]

Hello guys,

I run the car now and then went to 40kph speed then set the Transmission to neutral. Rumbling is still their. What would be the problem?

Drivetrain and/or tires. Hard to tell exactly what from this end.

 

[wilt]

Try turning the car somewhat quickly to one side or the other, and increase noise in one direction is symptom of greater loading of the bearing in one direction.

 

[toksis]

I will try that turn to the other side directly. Should the speed still 40kph?

 

[wilt]

I will try that turn to the other side directly. Should the speed still 40kph?

The point is to try to start at the highest volume of sound while in straight line, unloaded state, then put load on one side (then the other) to see how load change affects the sound. Of course, doing so safely is important. If you can go to a large empty parking lot during the test antics, like sunrise on Sunday morning, great! No risk to others, lots of empty space for you to recover from being overly distracted conducting your test. The more clues you can provide the mechanic, the better that the trouble can be localized, diagnosed and properly fixed.

 

[toksis]

Hello,

I went to the dealer, and let him experience the sound. He told me that it is the tyre, I need to change the tyre after 10k. He also experience it on his A5 Audi.

 

[toksis]

I will still try that advice wilt

 

[wilt]

To me, tire noise transfer is rather different than the metal-on-metal noise transfer of a bad bearing. Tire noise has a higher component of 'aural' (what you hear via air transfer, with windows rolled up vs. down). What is the calendar age of the tires (...see production date code)?

 

[toksis]

For me, you can hear the noise when the windows is closed. So its Aural.

Back left DOT LMT4 A149 3108
Back right DOT LMT4 A1H9 3006


Front left DOT LMT4 A1H9 0310
Front right DOT LMT4 A1h9 0310

Thanks for replying.

 

[wilt]

One tire made in 2008, nearing what manufacturers say is replacement time. One made in 2006...8 years into its life, really ought to go into retirement. The 2010s are fine.
Department of Transportation recommends changing even new-looking tires once they hit 10 years old, and many manufacturers recommend swapping them out at six years old. Rubber deteriorates over time due to UV and environmental exposure and the result leaves tire structure brittle and more prone to failure...brittle rather than compliant...affects road noise production.

 

[toksis]

Thank you very much. I think i need to replace the tyres. Thank you.

 

[DSXMachina]

Award

You get the trophy for "Worst Video of All Time Demonstrating a Complaint About a Noise".

Truly awful. Surely you posted the wrong video, maybe the one where at midnight you were testing out your camera in a closet?

But yes, I agree, it's the tires.

 

[toksis]

Did not focus on the video, I want you guys focus on the noise