[Wengy]

Ok, below you'll find a link to a YouTube video. There's no picture, it's only a sound recording (it's the only way I could figure out to get a soundfile posted for people to listen to). Turn it up, way up, so you can hear it (Don't worry there's no sudden surprises in volume, I was alone in the car and not talking).

http://www.youtube.com/watch?v=79D0ZYgaGEM

Now this clip was recorded when I was driving the car.

- Going about 50-60kph
- 3rd gear
- 2500 - 3000rpm
- Coasting down a long straight piece of road, applying the gas on and off.

You can hear the sound from the very start of the clip. It's not the smooth droning engine sound but the slightly higher pitched grinding or rattling sound which comes and goes intermittently as I apply gas. The sound goes away at higher rpm and higher speeds, it also doesn't seem to happen when the engine/transmission is under any real strain, like going up a hill for example. It seems to happen when I'm driving leisurely, down a slight hill or long straight, coasting and applying light gas.

I want to know if this is just another common "M" sound, or if it's indicative of some other issue. The car drives fine, and I've noticed no problems whatsoever.

[M3_JD]

sounds like it could be the typical exhaust rasp that these cars have

[Wengy]

No, it's not the rasp.

[m3e46freak]

More information
but...check subframe areas for lose stuff and diff..

[Wengy]

Ok, thanks for those suggestions. I've just update the OP to include a recording of the sound, please have a listen and let me know your thoughts. Thanks guys.

[John_T]

Where is the sound coming from? Sounds like when torque is off the drive line, the drive shaft center bearing is grinding.

[Wengy]

Originally Posted by John_T

Where is the sound coming from? Sounds like when torque is off the drive line, the drive shaft center bearing is grinding.

I don't know exactly where it's coming from, my impression is it's coming from directly underneath or slightly behind me (but that's just an impression, I recorded that sound with a device which I held pretty much above the center console). But I haven't tried to recreate this at a standstill, and I can't hear it with the windows down driving past a reflective barrier or some other wall. It's only really apparent at these slow speeds, when the car is under light loads and coasting. When I apply a little gas, I get this sound, it's pretty faint, but still noticeable.

[SPDboyNY]

I would take it to a garage and have them put it on a lift and run it up to speed, maybe they can hear it better in the air.

[John_T]

Originally Posted by Wengy

I don't know exactly where it's coming from, my impression is it's coming from directly underneath or slightly behind me (but that's just an impression, I recorded that sound with a device which I held pretty much above the center console). But I haven't tried to recreate this at a standstill, and I can't hear it with the windows down driving past a reflective barrier or some other wall. It's only really apparent at these slow speeds, when the car is under light loads and coasting. When I apply a little gas, I get this sound, it's pretty faint, but still noticeable.

The center bearing is about under your elbow on the arm rest in the tunnel below that. I have blown a couple in previous BMWs and the symptoms sound similar to yours.

[Wengy]

John_T. The center bearing along the driveshaft? Can you indicate which part it is here? Granted this is just your guess at this point, but it's somewhere for me to start looking at the very least. Can you tell me what it cost to repair the center bearing when you had it done, and how I might go about diagnosing it? There's no shudder or squirming when I accelerate, wouldn't that normally be a symptom of a driveshaft component failure?

Note my car is a 2001 with only 38,000kms on it.