I have had a very annoying and rather loud noise coming from the passenger side of the rear strut bar shortly after reinstalling a set of 08 OEM struts and springs. The noise almost sound like the rear of the car is loose and will come apart!

The sound is very similar to what others have recorded:

VIDEO1 by forged93

VIDEO2 by Carlili4190

As you can hear, the rattling noise can be fairly high pitched and seems to be coming from the interior but after removing all the interior plastic trim pieces and using dynomat/sound proofing foam, I realized that the noise only sounds like it is coming from the interior but really is coming from the suspension.

I have been following closely on the forum especially this epic thread LINK

Like others in that thread, I have tried various fixes without success. I have just learned to accept and live with it (mostly by turning up the stereo). But today I made a last ditch comprehensive effort to correct the problem and it worked! I think my ears can't believe how quiet the rear is now! I tried various fixes to no avail. I think the solution has been so elusive because:

1) Due to the design of the 350Z, especially how the top of rear struts enter into the cabin, even small suspension noises can resonate and be amplified. Also, there really is not a lot of sound proofing in the rear. The Z is therefore very prone to noise issues coming from the rear.

2) As many people on the forum have described, the problem can be temperature sensitive (e.g worse during cold temperature)

3) There can be more than one source for noise in addition to the suspension. In the past I have tried to correct one potential problem only to find that the fix did not work because there are still other sources of noise that I failed to do at the same time.

 

The following are what I did today to finally fix the noise problem:

1) There has been reports on other forums that the rubber pieces at the top of the struts dry out and create noises by rubbing against the metal pieces. I think this may account for the higher frequency rattling noises. I disassembled the struts and used white lithium grease to lubricate the various contact areas. This could be the temperature sensitive source of noise.

 

2) Following the post by Nismo542:

LINK

I found some nylon spacer at the hardware store (size 5/8 x ½ x ½). I cut and sanded to fit the mounting hole at the lower part of the rear strut where the bolt goes through. Please note that the size of the spacer may differ depending on what type of suspension you have. I am currently using a set of 08 OEM struts. IMHO this is the source of the clunking type of noise.

I have made my own custom rubber gaskets to replace the dried up brittle gaskets in the past, but did not find that this to be very helpful. My current noise-free setup still uses the dried up old gaskets.

3) For extra insurance, I stuffed some carpet into the space above the rear strut in the strut bar. In the past others have used memory foam or expanding foam.

4) Make sure you torque all the bolts to spec when you assemble and put back the struts.

 

If you still experience any noise after correcting the above, make sure you check other sources of noise not coming from the suspension and try the fixes below:

1) Rear axle clicking: There is a TSB on this. See:

LINK

2) Hatch gas hydraulic arms noise and the rubber band trick

LINK

3) Other hatch noise issues:

LINK

I hope this post will help those faced with a similar noise problem so that that we can enjoy some peace and quiet while driving the Z! If anyone has any other suggestions or comments, let me know so I can change the post.

 

Drove a 2004 and experienced the same problem. Assumed it was the gas filler assembly.

 

thanks for this.

 

Great write up!

 

I am going to have to try this. How much did you have to cut and sand the "spacer"?

 

Def trying the rear strut method and the hatch strut method!

 

I had to cut off about 2/3 the length of the spacer. I only sanded lightly the spacer with the dremel, did a test fit, and sanded some more as needed.

 

heres a link to an older thread with some more detailed pics etc.
https://my350z.com/forum/maintenance...e-for-4-a.html

 

Thanks but this is the same link that I posted under post #3 above. This is a crucial step in getting rid majority of the noise.

 

for some reason the thumbnails don't work.

 

Does anyone with this problem experience the rattle while the car is at idle. It will happen intermittently then suddenly stop, this makes it hard to really pinpoint its location. Thanks.

 

I found my rattle it was where my CXRacing (HKS replica) drivers side pipe crossed over the rear sway bar in front of the differential. I just wrapped some radiator hose around the sway-bar and zip tied it so it would stop clanking together. This is after being under my car over 5 times beating the crap out of the heat shield that is right before the differential in that area, it made sense at the time that that was what I was hearing.

 

Any updates from anyone trying the fixes?

Winter is rolling up and the cool weather brought my little sounds from the rear back again.

 

Thanks again for posting this !!!

Question, where do you put the carpet "space above the rear strut in the strut bar"

Do you mean against the body of the car where the strut would attach to the body?

 

No I meant the space above the shock once installed. It is the area in the rear strut bar which I think may cause sound to resonate and become louder.

 

I can confirm this solution works, at least for the moment.
I did this today and the rear is now silent.

The clunk most probably comes from the strut fork where the bolt is thinner than the hole. When I looked inside the hole I saw that on a spot the metal was shiny and supposed that there was the hitting point.

I didn't have a pipe to cut the spacer for the strut bolt but found two O rings which fitted. I'll keep the O ring for now but I will find someone to make me some spacers from copper or polyurethane.

I hope it lasts in time.

 

That's great that this helped you. What does your O rings look like? How long do you think they will last?