CX-7 Rattle When Accelerating

[Misty]

So I own a own Mazda CX-7 with 102k miles on it. Intermittently when I accelerate I get a rattle noise that sounds like it's coming from the rear. If my window is down - it is pretty loud - sounds like a marble getting shook in a can or something. I can also hear it in the car with the windows up but it's obviously less noticable.

This happens if I'm accelerating hard to pull out into traffic or getting on the highway, etc.

Any ideas what it could be?

TIA

[KiwiFlavor]

Is your spoiler loose? Maybe the screws that hold the spoiler in place fell out. only thing i can think of.

Where in NH are you?

[Vansquish]

Sounds like it could also be a damaged rear diff...

[robbspeed]

Your positive it's coming from the rear? Any chance you could grab a recording of the sound?

[robbspeed]

Originally Posted by Vansquish Sounds like it could also be a damaged rear diff...

If that's the case what would be the best way to confirm? Drain the diff and look for wear metal? Or jack up the rear, grab the wheels and turn them back and forth to check for excessive play?

[Misty]

My rear diff was worked on a while back and should be perfect - that was for a constant low humming sound that was increasing as days went by. The work took care of that noise instantly (thank goodness). But the rattle is a different sound. I could try to record it but it's only while I'm driving and it's intermittent.

I don't have a spoiler, so it's not that. Perhaps I should get my husband to go under the car and see if anything is loose (nuts/bolts/etc)?

I'm in Loudon NH

Originally Posted by robbspeed If that's the case what would be the best way to confirm? Drain the diff and look for wear metal? Or jack up the rear, grab the wheels and turn them back and forth to check for excessive play?

I'll have husband do that as well. But as I mentioned, it was just worked on a couple months ago so I don't think that's it, the car did the rattle thing before they worked on the diff so I would assume it would have been taken care of since the other noise was eliminated. What do you think? Sorry, I'm totally not a car person - your opinion is super helpful!!!

I definitely think the sound is coming from the back and not the front - but perhaps it's in the midsection of the undercarriage?

[robbspeed]

It could help if you grab a recording of the sound the next time your in the car. Keep us posted either way.

[Misty]

So I attempted to record the sound while driving and was only able to duplicate the sound once out of maybe 12 accelerations, and my recording is not the greatest. It seems like when I TRY to make the sound nothing happens. And when I least expect it - there is is. LOL - frustrating. Not sure how to attach the sound, I used my video recorder on my phone.

[robbspeed]

Originally Posted by Misty So I attempted to record the sound while driving and was only able to duplicate the sound once out of maybe 12 accelerations, and my recording is not the greatest. It seems like when I TRY to make the sound nothing happens. And when I least expect it - there is is. LOL - frustrating. Not sure how to attach the sound, I used my video recorder on my phone.

I think you just scroll down to "manage attachments" and when you're leaving a reply. Then locate the file, whether it's under "videos" or "sound recordings" or whatever, then upload it.

[mazdaspeedchris]

30 years of owning my own shop I can tell you no one on this site will be able to help. Recording it is a waste of time. Couldn't tell you how many times over the years I have had calls about rattles or noises that the customer wanted a diagnoses over the phone. Take it to your mechanic and have him drive it.

[MRR]

Could be the exhaust muffler.

[cdtech20059]

Originally Posted by Misty So I own a own Mazda CX-7 with 102k miles on it. Intermittently when I accelerate I get a rattle noise that sounds like it's coming from the rear. If my window is down - it is pretty loud - sounds like a marble getting shook in a can or something. I can also hear it in the car with the windows up but it's obviously less noticable. This happens if I'm accelerating hard to pull out into traffic or getting on the highway, etc. Any ideas what it could be? TIA

Hi Misty has this issue been resolved or located? I am having same issues. 2010 cx-7 turbo FWD. I heard it once while accelerating; sound is coming from under-neither maybe rear passenger side trunk area. Sounds like a rock going through pipes with a slight rattle. It is wifes car and she told me she just started putting in 87 octane. DUHHH told her not to do that. Maybe that is the issue? I will check for loose items this weekend.

[CX-7Pilot]

I would be very suprised if was coming from the rear and sounds like that. I’m about to post about a rattling I was hearing that very closely resembles the marble sound you describe except that it was under boost and coming from the FRONT of the car. You probably have detonation happening.

Any codes from the OBD II?

Otherwise if you’re certain it was from the back, I’d check the muffler to see if maybe some rocks didn’t fall into it from the exhaust tips. Best to have a mechanic look at it if you’re not sure as you could be doing some damage.