Mystery noise (audio)

[NorCalZman]

Mystery noise time. Listen carefully to the whole thing (headphones maybe?). My phone is recording audio under my passenger floor mat up against the front firewall. I am stopping and starting the car leaving a parking lot, and making a turn at some point before accelerating up to speed to another stop. Noise happens in all instances (don't think its related to brakes).

https://soundcloud.com/socalzman/car-noise

[NorCalZman]

Solved. mechanic sourced the noise to the subframe. He said the bolts were not loose so I am not sure how it was making all that noise but they reset the subframe and its bolts and the noise stopped. Car is totally quiet and solid. All I had to pay was an hour of labor. I am happy.

[alexandre]

I have a similar noise and was suspecting the same as my entire suspension is brand new. Glad to know it was a simple fix. I'll have mine looked at stat!

[slater]

front or rear subframe?

[NorCalZman]

I have a similar noise and was suspecting the same as my entire suspension is brand new. Glad to know it was a simple fix. I'll have mine looked at stat!

Yeah? I have googled front subframe noise and it is VERY common on Volvos and VWs but yours is the only other e46 I have seen. I am kind of glad I am not the only e46 with this issue, haha. Mechanic said he has had to do this on some X SUVs but not a e46. They found the source by putting the car on a lift that was under the wheels (not jackpoints) and turning the wheels left and right and followed the creaking. Then the supported everything underneath, loosened some of the bolts, and retightened everything to spec. Noise gone. only had to pay one hour labor. Take a look and report back, please.

front or rear subframe?

Front subframe.

[NorCalZman]

looks like this issue might be more widespread on e46s. http://forum.e46fanatics.com/showthread.php?t=1052922

If you have any groaning or popping coming from your front end you might want to get this checked out.

[derbo]

Solved. mechanic sourced the noise to the subframe. He said the bolts were not loose so I am not sure how it was making all that noise but they reset the subframe and its bolts and the noise stopped. Car is totally quiet and solid. All I had to pay was an hour of labor. I am happy.

Glad you found it Antone!

[alexandre]

So I've been reading about this and most people with this mystery sound traced it to the front subframe or the chassis reinforcement plate. Turns out the latter's 8 bolts are single use. I must have removed and reinstalled them 3-4 times since I've been driving this car...

I just ordered the 4 front subframe bolts and 8 reinforcement plates bolts for $35.04 at FCP. I'm gonna replace all of them and torque them to spec - I'm really hoping that this makes the sound go away. I'll post an update in this thread when I do the job!

[NorCalZman]

keep us updated. Are you going to do one at a time (subframe first then plate) to find out which is making the noise or just replace both?


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[alexandre]

It'd be better to isolate the problem... But then I don't fancy jacking the car twice, it's enough of a PITA as it is in my inclined driveway! I'll see what I'm down for when I do it.