2024 GT rear passenger C-pillar creak/rattle over road vibrations

[OH_5.0]

I recently picked up a 2024 GT Premium 401A with about 8k miles. The car drives great and overall I'm extremely happy with it but I'm chasing a noise from the passenger rear area that is driving me absolutely nuts.

It's somewhere between a creak and a light rattle, almost like a small pebble bouncing around a metal bowl. It seems to be triggered by small vibrations from the road rather than large bumps. I hear it more on rougher pavement and at higher speeds. The sound seems to come from the passenger rear C-pillar area.

Things I've already tried:

• Removed and reseated the passenger C-pillar trim
• Added foam behind most areas of the C-pillar trim, all around the airbag mount, etc
• Removed the child restraint/latch cover
• Lubricated and taped the rear seat latches and receiver
• Eletrical tape all of the clips with the C-pillar trim
• Tried driving with the rear seats folded down and seat belts buckled
• Checked the trunk for loose items

Another observation is that the noise seemed quieter and less frequent when my daughter who weighs about 100lbs was in the car. It didn't matter much whether she was in the front passenger seat or either rear seat. Could have been coincidence with the road conditions but I also noticed once that the noise seemed to stop while going around a turn although I wasn't paying enough attention on the direction I was turning but it made me wonder if vehicle loading is affecting whatever is making the noise.

I've seen a few threads here about S650 rear passenger rattles eventually being fixed by the dealership replacing the rear shock but I'm wondering if anyone has experienced this particular type of noise or has any other ideas for what I should investigate.

I'd really like to diagnose this myself if possible before taking it back to a dealer. I had it there once and they said it was the car seat latch covers. Thanks!

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[D/\rK•650]

Have someone drive and sit back there and push on things and try to track it down more. Seems like you did quite a bit a troubleshooting already but maybe sitting back there would help to pinpoint the exact location.

 

[OH_5.0]

Have someone drive and sit back there and push on things and try to track it down more. Seems like you did quite a bit a troubleshooting already but maybe sitting back there would help to pinpoint the exact location.

I plan to do this today!

 

[D/\rK•650]

I plan to do this today!

Well Goodluck with it and I hope your able pinpoint the issue.

 

[Sofa King]

The drivers side C-pillar cover on my '24 made some noise when I first got the car... it wasn't clipped in all the way. Once I got it clipped in better it has been quiet. I'm sure you probably checked that all of the clips are there and intact... other than that...?

 

[Corpisoturi]

I hear the same thing in my car from the exact same place and the same sound. I have a 2024 GT.

Of course, to me, that sound sounds like someone picking at a plate with a fork. And that sound comes up every time you drive into a pothole.

 

[OmegaDH]

I test drove a 26 GT that had this same problem. So I went with a 26 Dark Horse and there's no problem. A thing to note, GT was a stick and the DH is automatic.

 

[OH_5.0]

I think I found the issue. After trying pretty much every suggestion I could find on the forums and YouTube, electrical taping every latch and clip, lubricating every hinge I could find and driving with the rear seats up and down nothing fixed it.

The one thing I noticed was that the rattle would almost completely disappear whenever I had an adult passenger in the car whether they were sitting in the front passenger seat or the rear. That got me looking more closely at the rear suspension.

While looking around the passenger rear wheel I noticed that the rear wheel well liners use these spike/knob type fasteners to hold them in place rather than the push-pin style fasteners used on the front liners. Every single one of them on the passenger side was loose and barely holding onto the threads.

I tightened all of them down and took the car for a drive and there was no rattle. I came back and checked the driver side as well. Those were tighter than the passenger side but all could still be tightened further.

I obviously need to drive it some more to confirm but that was the quietest the car has been while driving by myself since I bought it.

My current theory is that the loose wheel well liner had enough play to vibrate against the body from normal road vibrations with the sound being transmitted up through the rear quarter/C-pillar area.

If it stays quiet I think this was the issue.

 

[Will2]

these spike/knob type fasteners

I have multiple weird noises from that corner of the car and will try your fix.

How do you tighten em down, just push twist a certain way?

 

[OH_5.0]

I have multiple weird noises from that corner of the car and will try your fix.

How do you tighten em down, just push twist a certain way?

Yes they just twist down like a typical nut, there are studs they screw on to.

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