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Metallic rattle from rear passenger's wheel well.

Messages
219
Reactions
95
Points
27
Location
Nevada
Vehicle
2025 ST
#1
This one has been a challenge. 2025 8800 miles.

Rattle present for months, prior to suspension work. I thought it was the tools I had stored in the rear rattling but after removing the tools the rattle still existed.

Metallic rattle on passenger’s side rear wheel well area while driving over road irregularities. Sounds very loose, will rattle with the slightest road irregularity. Will rattle regardless of the weather or vehicle being hot or cold. Small road irregularities will cause it to rattle at a high frequency and large bumps will cause it to rattle matching the larger frequency. Please see photo for location.

Have checked (likely forgot a few) with no change, rattle still present:

Under vehicle-

Rear sway bar end links replaced with factory.
Rear shocks swapped side to side. Removed rear shock on passenger’s side and road tested, no change.
Checked torque on control arms and links.
Checked for interference and rattles from AC lines.
Checked fasteners for AC lines.
Checked spring isolator.
Removed fender liner, checked for possible cause.
Checked heat shields.
Checked wire brackets and brake line bracket attached to fender.
Exhaust hangers and general clearance.

Interior-

Removed panels looking for source.
Checked cavities in unibody for source.
Checked seat belt mounts and retractors.
Checked torque on everything in the quarter panel including HVAC housing.
Checked AC lines.
Checked third row seat bracket for possible source, no change.
Installed missing fasteners in the duct work.

Sounds like this, although gets louder at times. https://photos.app.goo.gl/23ro8PDENcNho71t5

The location of the sound is specifically identified in the photo.

IMG_0102.jpg

Ideas?
 

Messages
46
Reactions
21
Points
2
Location
MO
Vehicle
2026 ST AWD
#2
I wonder if that joint needs (needed) seam sealer from the factory. Have you given that area (the wheel well, the panel on the well) the old light "palm strike"?

Great detective work by you. Pretty frustrating to have a rattle on a low-mileage 2025.

/edit/:

Is there anything in those channels?

The sound is very mechanical, "clicky". Suspension part is suspected because, as you said, the noise occurs with any change in the road surface. Brake component? Have you (gently) tapped stuff in that area with a rubber mallet? Yank up and down on the passenger side axle (suspension unloaded/drooped)? And, push/pull the wheel while the suspension is drooped? Something in the spare tire well?

/end of edit/
 

Last edited:
OP
S
Messages
219
Reactions
95
Points
27
Location
Nevada
Vehicle
2025 ST
Thread Starter #3
I wonder if that joint needs (needed) seam sealer from the factory. Have you given that area (the wheel well, the panel on the well) the old light "palm strike"?

Great detective work by you. Pretty frustrating to have a rattle on a low-mileage 2025.

/edit/:

Is there anything in those channels?

The sound is very mechanical, "clicky". Suspension part is suspected because, as you said, the noise occurs with any change in the road surface. Brake component? Have you (gently) tapped stuff in that area with a rubber mallet? Yank up and down on the passenger side axle (suspension unloaded/drooped)? And, push/pull the wheel while the suspension is drooped? Something in the spare tire well?

/end of edit/
Yes I have ran a mallet over nearly everything inside and out. I can rock the vehicle back and forth and nothing, only present while driving. I am not able to get anything to make any noise while tapping. I even ran a magnet inside every cavity I could find to see if there was any loose metal. I also ran a long zip tie into cavities to feel for anything loose. I even removed the shock and looked for something loose behind the threaded inserts in the body which secure the strut mount.

This one is a tough one, I am usually pretty good at finding these but this one so far has been challenging.

It is odd to have a loud knocking right in front of you at the wheel well then have no idea where it is coming from.
 

Messages
46
Reactions
21
Points
2
Location
MO
Vehicle
2026 ST AWD
#4
SugarMouth,

That's some thorough work! At least you've narrowed down the location. It's maddening that the source of the rattle remains elusive - for now.

I've seen a set of "mechanic's microphones" which would be placed on various parts in the rear PS wheel area that should go a long way to finding the offending item. Each microphone reports to the receiver and the resulting traces tell the story.
 

Messages
1,907
Reactions
1,621
Points
262
Location
Utah
Vehicle
Exploder
#5
I'm sure you've looked at the muffler hanger bushing? They've been known to transmit noise into the body.
 

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