Loud annoying noise from the rear end.

[Rafichicago]

So I got my Z4 few months ago. It's 3.0SI manual. It has 97K currently. Coming from many different cars it had unbearable noise from the rear. Fires I thought those are wheel bearings. I've replaced those with all of trailing arm bushings. Replaced tires and ditched run flats. All that made car quieter but still loud. Even in comparison with E46 convertible. I realize this is not a highway cruiser, but hey. It doesn't hurt to improve that I have purchased some sound deadening material and have used it inside the trunk area. It helped but only marginally. I have ended up removing wheel well plastic, cleaned it and placed some more material there. That done the trick. It's not quiet by any means but made the car much nicer to drive. I might be more sensitive to certain sounds that the others that's why it bothered me a lot. Honestly when top removed it doesn't bother me at all. But with it closed, the sound was driving me nuts. So anyone that is trying to improve car in that regard it's well worth it in my opinion. The whole material wasn't too thick. I added maybe 5lbs if that. I thought I share my experience

[Our03z4]

First of all in response to the thread title, certain foods can unfortunately do that.

As far as the car, they are noisy. You have to remember that you are basically sitting on the rear wheels. I had added drilled and slotted brakes on my roadster and the noice drove me insane. Any little thing you will hear. The coupe isn't bad at all. Adding deadening material in the trunk may help but you are still going to be over the tires with just a thin top between.

[Piper1]

Did you find what is creating the noise you’re hearing? The loudest thing from the back of my roadster is the exhaust. Granted it’s a supersprint but still. While back there did you change the diff fluid? I can understand if you’ve got excess tire noise than what you want, remember you’re just about sitting on top of the rear axle, but I’d want to know exactly where the noise is before muffling it.

[Rafichicago]

Thanks for responses guys so yeah. It kind of is combination of tire noise wheel bearing noise it just is pretty loud for me. I have replaced diff fluid when I got the car few months ago gearbox fluid replaced as well. And yeah after replacing tires and bearings I know it's just nature of the beast as you've said you are literally right at the rear axle so that is why. I just shared my opinion and what I have done to help it a little. That's all it's just specific type Od sound that bothered me but it is much improved now with what has been done.

[tvn300]

Hi Rafi, I'm a new Z4 owner, and just as aggravated with that noise as you are! What material did you apply? And I'm assuming that is was applied to the "not visible" side of the wheel well liners? How thick, etc. I would love to quiet it down a bit. I did not notice anything with the top down, but closed up, its quite loud! Thanks, Tom

[Rafichicago]

Originally Posted by tvn300

Hi Rafi, I'm a new Z4 owner, and just as aggravated with that noise as you are! What material did you apply? And I'm assuming that is was applied to the "not visible" side of the wheel well liners? How thick, etc. I would love to quiet it down a bit. I did not notice anything with the top down, but closed up, its quite loud! Thanks, Tom

This is what I have used.

https://www.ebay.com/itm/30255857057...#38;media=COPY

I have removed rear fender liners. Cleaned underneath dried it out because you don't want to trap any moisture there. Removal is pretty simple. There's one 8mil under the car in front of the rear wheel. Don't forget about that one.
I also removed carpet from trunk and did everything there. Make sure to lay everything even and press against the surface tightly. There might be thicker material that will absorb sound better but I'd be careful since there isn't tons of distance between fender liner and metal.
Good luck !

[maupineda]

How much weight do you think you added? I don’t mind the road noise. But if it makes the car feel more solid. Maybe a good trade off

[Rafichicago]

Originally Posted by maupineda

How much weight do you think you added? I don't mind the road noise. But if it makes the car feel more solid. Maybe a good trade off

I don't think this was more than 5-7 lbs if that.the noise was only annoying with roof up.

[kaybat]

It's normal on this platform, my 03 and 06 both were noisy back there...

[Rafichicago]

Originally Posted by kaybat

It's normal on this platform, my 03 and 06 both were noisy back there...

I've heard same thing. Nothing that 7-10lbs of deadening material cannot resolve. It's not ideal but makes longer drives much more pleasant. Those cars are not the quickest anyway so extra weight doesn't really matter. Nothing that good diet cannot resolve 😉🤪 All in all in my opinion well worth the effort. I have also placed this material underneath that plastic parcel shelf.
One more thing. I have first placed that material in the trunk. Honestly it helped but very little. Removal of wheel well covers and placing that material there made all the difference.

[vt100]

Originally Posted by Rafichicago

So I got my Z4 few months ago. It's 3.0SI manual. It has 97K currently. Coming from many different cars it had unbearable noise from the rear. Fires I thought those are wheel bearings. I've replaced those with all of trailing arm bushings. Replaced tires and ditched run flats. All that made car quieter but still loud. Even in comparison with E46 convertible. I realize this is not a highway cruiser, but hey. It doesn't hurt to improve that I have purchased some sound deadening material and have used it inside the trunk area. It helped but only marginally. I have ended up removing wheel well plastic, cleaned it and placed some more material there. That done the trick. It's not quiet by any means but made the car much nicer to drive. I might be more sensitive to certain sounds that the others that's why it bothered me a lot. Honestly when top removed it doesn't bother me at all. But with it closed, the sound was driving me nuts. So anyone that is trying to improve car in that regard it's well worth it in my opinion. The whole material wasn't too thick. I added maybe 5lbs if that. I thought I share my experience

Have you checked the diff and the central bearing?

[Rafichicago]

Originally Posted by vt100

Have you checked the diff and the central bearing?

There's no vibration or whine that diff would be making. Differential oil has been replaced and was clean.

[jwolf]

If someone replaced the stock diff bushings or suspension bushings with poly, the noise is going to get transmitted into the body. I have the poly diff bushings and I hear the diff. Did not with stock. The ability to chirp the tires going to 2nd gear was a surprise with this more direct connection. So much of a car's direct connection with the driver has been forced out of the design. If it was my daily, I would not care for all the directness feel.

[javis20]

Why didn't you apply it to the plastic wheel well liner, instead of the metal body?

[Rafichicago]

Originally Posted by javis20

Why didn't you apply it to the plastic wheel well liner, instead of the metal body?

I didn't think it's going to hold up to the plastic and honestly with such a thin metal that's used on this car I thought that it will help with resonance of it.

[07ImolaRot]

Are you sure you arent hearing a clunking noise related to the rear shock mount? Those are notorious for making noise

[Rafichicago]

Originally Posted by 07ImolaRot

Are you sure you arent hearing a clunking noise related to the rear shock mount? Those are notorious for making noise

It was never clunking that I have complained about. And it's taken care of now👍