JohnMC

I have had my RX-8 for about 10 months now, and I have noticed a serious rattle in my back end. It is a loud noise that I hear on rough roads and when I hit a pothole, bump, or seam in the concrete. I am at a loss to find out what is causing it. When I am on smooth roads, there is no noise. As soon as I hit a rough road or a bump, the noise is very loud. I tried removing my spare tire kit, no help. I had the trunk adjusted, no help. Perhaps the trunk hinges are causing the problem, I don't know. The dealer says that there is no problem with the suspension. Has anyone else had this problem or have any idea what is causing it? Thank you.

PoLaK

iTrader: (1)

There have been quite a few people that have problem with the differential. Thats what this sounds like to me. If you can live with it for a while and your dealer doesn't want to check your differential have him make note of a noise coming from the rear end.
Then when your past break in, drive the car harder my bet is it will break.

Since the problem goes away on smooth roads i may be wrong but its worth looking into.

Ole Spiff

If you have the spare tire kit, check to see if any of those pieces are loose, or one of the tools in the kit box are loose.

Spin9k

Here's two things to look into. Had car at dealer, up on lift with mechanic looking for noise from driver's side rear suspension. He never did find the source of the noise, although we both hear it, a rattle like a loose sway bar or strut loose inside. Esp. noticeable at slow to low speeds over rough payment.

Anyway, we're talking and he shows me what he has noticed on all RX-8s on passenger side at the muffler hanger how it is angled up. Sorta like this "\" rather than "|", pointing towards the front. He says that they are all like this for unknown reasons, and that it makes the hanger bracket much closer to the frame, with possibility of hitting the frame as the muffler and car flex. That would be a direct metal on metal contact. He says it is a mis-placement of the hanger anchor on the frame. I hadn't heard that particvular noise, but with a little push on the muffler - ting ting metal on metal.

As for my problem, even though dealer can't find the problem, Speedracer says he and others have has a similar noise and found the sway bar end links need to be torqued full tight, then just backed off, or they get a noise like that. Have to tell the mechanic next visit.

Maybe this will help you.

rX-n-sa

If the sound seems to be coming from the trunk area then it may be the same problem I had. There is a speaker amplifier mounted under the rear window that has to be accessed from the trunk. Mine was loose and after about 3 trips to the dealership with no success, this is what it ended up being. After they fixed it, no more rattles.

StewC625

Whenever you get a strange rattle, first thing to do is remove ANYTHING loose from the car - and for that matter most everything else.

The funniest rattle I ever had was after my Acura TL came back from the dealership after having a fuel pump issue resoved (it started to make an audible whine) - to fix it they had to remove the back seat.

Well, I get the car back, and as I go over bumps, there's a clank from around the rear axle area - not every time, but often enough. I ignored it until the next oil change, figuring my spare was working loose, and I'd have my Acura dealer tighten it up.

Turns out it wasn't the spare - the tech that fixed the fuel pump had left a nice Snap-on ratchet handle under the back seat. Too bad I didn't diagnose that one myself! Could have used that ratchet!

cgrx

Do you have an aftermarket exhaust ? Could be hitting the heat shield......

JohnMC

Thank you for the advice everyone. My car had the problem where the trunk was hitting the taillights. I had marks developing on the taillights. I thought that this is what was causing the rattle. I had this fixed when I read the Mazda TSB on the issue. However, that did not take care of the rattle. I even tried driving with the trunk open to see if maybe it was the trunk latch or something, but it made no difference. Originally, actually, I thought it might be the muffler so I upgraded to the MazdaSpeed exhaust. That didn't rectify the problem either, but it could be that they just installed it using the exact same mount positions as the factory. Now I am thinking of replacing struts, sway bars, & sway bar end links. I don't know what to do at this point because it is really spoiling the whole ride.

cgrx

Check the exhasut heat shield, you'll see wear marks if that is the problem