Rattling noise at low speeds

Tiny
KEN DREGER
  • MEMBER
  • 2012 INFINITI M37
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 123,700 MILES
Our car started making a noise when driving 20-35 MPH on the roads back in June. I took it into the shop locally and they said that the front undercarriage pan was loose, and the wind was catching it and making the noise! So, I replaced it with all aluminum one and all new fasteners, still the noise persisted. Took the car back to the shop, they checked all the front end joints, struts, sway bar, lower & upper joints, the complete undercarriage. Nothing, Zip! The noise still was there. Decided to get all new rotors and pads, didn’t help, still rattle, rattle, rattle. Sounded like “Rocks”!
Took out the high-pressure gun one day and was washing the car, crawled under the side of the car, and noticed that the two body side panels that run from the back of the front tire to the front of the rear tire had an opening in the front of each one! Put the hose in there with a pointy nozzle and Woosh, out came a gallon of small rocks in total! Dang, how did that happen? Humm, our driveway is decomposed granite and lots of our local roads are chip and seal. Did it resolve the problem? Took it for a test ride, nope! Still there.
Dropped it off at our Infinity dealer on a Thursday, 11 days later I called to check, they haven’t even looked at it yet! Next day I get an email showing a list a mile long,
See below:
"Repair" that would resolve the rattling noise plus the leaking valve gaskets $1, 66.53, clean and treat the A/C vents $67.00, change the brake fluid $204.95, replace the inside cabin filter $130.00 and replace the spark plugs $360.00, fuel Induction service $259.95 and replace the front shocks for $1,335.00”.
Just "clump change" right! Not! Cabin filters are $4.00-17.00, opted out of the struts, plugs, fuel induction service ended up being $1,595.00 out the door! Called up our guy who did the brakes here at home and he came today and replaced the front struts for $785.00. Test drove the car and still makes the dang noise! Anybody have an idea on what might be causing this. The front-end parts checked out good, no movement in any of them. Replace the cardboard crap shield with an aluminum one also”.
Now I am still trying to figure out where and what is making the noise, so if anyone has an idea, please let me know...
Sunday, October 10th, 2021 AT 3:53 PM

10 Replies

Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

Rattles can sometimes be very difficult to find. I had shops that had special tech for noise alone.
Anyways can you possibly upload a video so we can hear the noise?
Can you tell if the noise is from the driver or passenger side?

Does it only make the noise at that specific speed?

Thank you.

https://www.2carpros.com/articles/rattle-noise
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Sunday, October 10th, 2021 AT 5:26 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Also, this is a perfect application for a tool called the "Chassis Ear". It's a set of six microphones, a switch box, and headphones. You clip the microphones to suspect parts, then go on a test drive while listening in the headphones and switching between them. I found the original kit on eBay for only $99.00. They normally cost around $200.00 from the guys who drive the tool trucks to the repair shops each week. This set has wired microphones, so you must be careful where you string the wires. A newer model has four wireless microphones, but it costs more.

Be aware a lot of mechanics have never heard of this tool or even seen it. Suspension and alignment specialists use them quite often when looking for the source of rattles and other noises.

If you need to get a specialist involved, the best place to go is to a tire and alignment shop. People at the dealership are used to working on relatively new cars that haven't had time to develop noises yet. The people at alignment shops are experts at finding the causes of noises, vibrations, and bad tire wear.
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Sunday, October 10th, 2021 AT 5:46 PM
Tiny
KEN DREGER
  • MEMBER
  • 6 POSTS
That Chassis Ear sounds like this is what my Infinity dealer should have used! I will ask around and see if anyone locally has one and can hook it up to our car or get one off Ebay. Thanks for the reply.
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Sunday, October 10th, 2021 AT 5:57 PM
Tiny
KEN DREGER
  • MEMBER
  • 6 POSTS
SQM- the noise as far as we can here happens around 25-35 MPH and on slightly rough roads, like a washboard road. Our roads here are all made of crushed rock with oil covering them, so we get a lot of uneven in all the roads. I will try to do a video Monday to see if it will record the sound also.
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Sunday, October 10th, 2021 AT 6:01 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Consider asking at some local auto parts stores that rent or borrow tools. In my city, they make you buy the tool, then you get a full refund when you return it. If you choose to keep a tool, you still return it, then they order or give you a brand new one.

You may not find this tool for loan because, so few people know about it or ask for it.

As the suspension and alignment specialist at the Chrysler dealership I used to work at, we had this tool supplied to us by Chrysler. I was one out of only two people who ever used it. I used it perhaps once a year, but it sure solved some elusive problems.
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Sunday, October 10th, 2021 AT 6:21 PM
Tiny
SQM
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As per caradiodoc 'chassis ear' is definitely a good idea.
It can help pinpoint the noise in most cases.
We will keep an eye out for when you upload the video.
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Sunday, October 10th, 2021 AT 6:30 PM
Tiny
KEN DREGER
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Well, I did this video today, if you listen carefully in the background you can hear the rattle.
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Tuesday, October 12th, 2021 AT 2:29 PM
Tiny
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It almost sounds like a wheel bearing. It sounds like a rotational noise.
Try this, drive on that same road, and try to swerve back and forth (do it in a safe manner), see if the noise gets higher as you are loading one side to another. This can tell us is the noise is from a bearing. As one side have more loading it should make louder noise.
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Thursday, October 14th, 2021 AT 9:53 AM
Tiny
KEN DREGER
  • MEMBER
  • 6 POSTS
I did the driving test and nothing changed in the level or frequency of the noise and I drove it hard.
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Friday, October 22nd, 2021 AT 10:19 AM
Tiny
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Got it. That rules that out. At this stage this will require that 'chassis ear' that we talked about earlier.
The noise sounds like a rotational sound and not a rattle. Which will require the vehicle to be driven for the diagnostics.
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Saturday, October 23rd, 2021 AT 8:21 PM

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