06 M35x Hum Noise

[dougdude9]

Hello,I have a '06 M35x with 34,000 miles on it and during an approximate 200 mile trip, I noticed a hum noise. My first thought was it could be the a/c. So, I turned off the a/c and still heard the hum. My second thought was maybe it was coming through the speakers (amp noise). I turned off the stereo and still heard the noise... didn't sound like it was coming from the speakers anyway.

The best way I can describe this hum is like a radio controlled airplane. I know that sounds weird, but that is what it sounds like. Maybe another example would be like when you are driving over grooves... like when you start to go off the highway and you hit those grooves that make that sound to warn you. However, it is not as loud as that.

The hum seems to get louder the faster I go. It is low pitched in general, but gets higher pitch as I go faster. I start to hear it around 30mph. If I slow down from 70mph, it sounds like the throttle of a radio controlled airplane is being reduced.

I did a couple of tests. I can tell you it is not related to the rpm's. I costed down a hill around 40mph, put that car in nuetral and rev'd the engine... this didn change the sound. I also put the car in park and rev'd the engine, this didn't create the sound. So, it seems to be related to how fast the wheels are spinning.

It sounds like it is coming from under the hood near the windshield, but it is hard saying... Kinda sounds like it is from behind the center bose speaker that is dead center in the dash.

If anyone has a suggestion on what this could be, it would be greatly appreciated.

Thanks in advance!

Doug

[M35 Sport]

Sounds like it could be a wheel bearing.

[dougdude9]

Thanks! I went ahead and made an appt with my dealer here in Kansas City. I thought I would ask around on here since my dealer normally doesn't get things right. I hope it is something simple and doesn't cost much. I know I'm under warranty, but it seems the warranty doesn't cover anything... I always end up paying.

Anyway, thanks for your input! I'll post back what it was if the dealer can figure it out.

Thanks,Doug

[dougdude9]

Ok, as promised, I would write back in here with what the dealer found out. I called today to see if my car was ready or if I'd be in the loaner for awhile. They said the found the issue and it was the front right wheel bearing.

M35 Sport... you were right!

I was scared that they would try to blame it on my new tires... seems some other dealerships were doing that when the wheel bearing was bad.

zer...noise

Anyway, glad I got it fixed. They didn't even have to order the parts which surprises me.

I just hope it really is fixed. I'm sure it is because the noise was pretty bad, so I'm confident they fixed the right thing.

Thanks,Doug