G35 Coupe V35 2003 - 07 Discussion about the 1st Generation V35 G35 Coupe

Coupe B pillar/back seat rattles

  #1  
Old 03-25-2019, 07:28 PM
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Coupe B pillar/back seat rattles

So I've had a new creak/rattle make itself known in the last year or so, but I've only really decided to try to go after it in the last month. it happens very slightly on bumpy/rough ground, but primarily right when I either accelerate or brake. It's a metallic groan/creak sound that appears to come from slightly rearward of where the coupe door meets the b pillar. I've already verified it is not the seat belt touching anything, I've already taken care of every cable inside the door itself, and the window is nice and snug. Thumping on the metal skin itself, as the panel is currently off, produces no sounds that indicate where it's coming from. I have already FatMat(ed) every interior sheet metal bit I can find. The seat belt retractor seems to make a very slight shaking sound when I tap on it, but I'm not certain that's the same sound at all. it comes from both driver and passenger side, but the passenger side definitely seems louder and might even be related to the other rattle I'm hunting.

The other major noise I'm hunting is the infamous marbles in a wooden cup sound only when the rear goes over a decent-sized, very short bump. I've removed seat belt retractors, rattle-proof and foam taped the entire back deck, done the TSB for the defroster plug in, but this rattle just will not go away. Again, thumping around on every surface does not produce the same sound, only very very faint vibrations I assume from a cable hidden up near the headliner (which I have also stuffed some foam into to prevent that). I am 99% sure that it is from the passenger side.

Aside from a few miscellaneous buzzes from the door where the plastic panel itself needs to be reglued together for structural integrity, these are the last major noises that I am hunting down before I will actually be relatively happy with my cars interior. Has anybody had any sort of noise like this, if so what's the fix? My commuting sanity depends on this (when your bombing down a back road, you don't repay as much attention to those noises!).
 
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Old 03-25-2019, 10:47 PM
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I get annoyed by little creaks as well. I would recommend hopping in the backseat while someone drives around so you can zone in on the noises little by little.
 
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Old 03-26-2019, 01:47 AM
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Originally Posted by Scorpi0 View Post
I get annoyed by little creaks as well. I would recommend hopping in the backseat while someone drives around so you can zone in on the noises little by little.
That's gonna require me letting someone else driving my car around...might be a sacrifice I have to make. I'll eventually find the backseat rattle (I hope), it's that creak that is terribly killing me. It sounds like the body itself shifting; possible something on the undercarriage that gets transmitted up? The window doesn't move at all, but it sounds like it comes directly between the window and the B-pillar. My W-brace under the exhaust was hammered in the middle to fit my exhaust; would that being weakened cause more body creaks by lessening chassis rigidity? Been meaning to fit some good braces on the body, but those are pretty expensive for not a whole lot of "spirited driving" gain...
 
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Old 03-26-2019, 06:19 AM
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Welcome to the life of a G owner. It's disappointing that a "luxury" car has so many creaks, squeaks, rattles, groans etc. and lot of them had some, if not all, from the factory. My 14 year old GTO makes absolutely no extraneous noises and hasn't from new to 60K miles. It is Australian built, the same can't be said for the American built Pontiacs from 2006...
 
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Old 03-27-2019, 02:07 AM
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Yeah, I resigned myself to thinking of G's as "350Z+" in interior quality a while ago, but I get like this with any sort of annoying sound regardless of the "luxuryness" of the car. I got pretty unlucky with my G in particular, first owner had it new to 109k, second owner thrashed it 109-119k, then there's me with it at 149k and a new transmission.

Sunk cost fallacy, and all that. My only real complaint is the interior rattles to be honest, the drivetrain is still in great condition and it's being hyper reliable in stupidly cold/hot conditions. When I can finally solve those noises, I can focus more on replacing odds and ends that need it.

I should probably save my cash for a newer/better platform (I've been tempted by a tan interior Miata for quite a while), but it's so hard to match the performance/aftermarket support for the VQ platform. Plus I'm a total sucker for the G's looks, coupe or sedan. If/when I replace mine, it's probably gonna be a VQ35HR sedan replacing it...or a 350Z I wouldn't mind so many noises in.

Still, I'm so close to eradicating those noises, they're just singular points I haven't gotten to yet. Was hoping someone else had had these noises, but looks like no dice or they're not online anymore.
 
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Old 03-27-2019, 08:28 AM
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I do know a few of my front/interior squeaks and rattles went away when I installed a front strut bar in the engine bay. Wouldn't help with back of the car issues though.
 
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Old 03-27-2019, 05:41 PM
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Never underestimate the power of a roll of 1/2" round foam insulation. You can poke it in just about anywhere you have interior rattles and it works great. Very useful around squeaky plastic panels.

Also use gorilla tape inside covered panels, and spray lube like tri-flow or All4 in places you can't reach.
 
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Old 03-27-2019, 06:50 PM
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Originally Posted by Blue Dream View Post
I do know a few of my front/interior squeaks and rattles went away when I installed a front strut bar in the engine bay. Wouldn't help with back of the car issues though.
Yeah, I've got a mediocre FSB (folks reached out and "asked any car parts you want for your birthday"? Chose a reasonable priced FSB (Megan Racing, big eh), on my doorstep next week. Thanks Dad!), and while the front feels better in corners, it didn't quiet a whole lotta noise up front (mostly got suspension noise and a glovebox creak, but it's not that bad). Been considering some of the upgraded underbody braces to see if those help.
 
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Old 03-27-2019, 07:02 PM
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Originally Posted by [email protected] View Post
Never underestimate the power of a roll of 1/2" round foam insulation. You can poke it in just about anywhere you have interior rattles and it works great. Very useful around squeaky plastic panels.

Also use gorilla tape inside covered panels, and spray lube like tri-flow or All4 in places you can't reach.
I've FatMatted the inner skin of of the rear, been spraying expanding foam in the cavity behind the rear seat belt retractors (interior panel passes way too much vibration to the retractors and make a shaking noise, foam seems to be helping). I think I'm on my second roll of 1/2" throughout the dash, doors, rear deck, etc.

Gorilla tape ON the interior of the plastic panels? I could see how increased mass would help.

As for lube, spray it between metal skins? I see a few places in the rear that it could be sprayed.
 
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Old 04-01-2019, 03:03 AM
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I've just remembered that there's been a hubbub about the sunroof causing noises on the coupes, and that I pulled a strange looking, golden nut from near the sunglass holder last summer (had heard rattling around). As far as I remember, the weird creak on accelerating/braking only appeared sometime after that nut came out. Anyone got specs on nuts above the headliner? No clue where that nut went.

Most likely gonna pull the headliner this weekend and take a look around, already have the rear quarter panels out (have been out for a week while I rattle-test), and at this point I can pull the upper rear panels in two minutes each (IIRC the A-pillars just detach and from there it's removing the "0h-****" handle and card holder and down she goes.

Gonna look like I'm driving a gutted drift car around at this point...
 
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Old 05-03-2019, 03:58 AM
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Quick update for anyone that stumbles on this, turns out the creak noise was my door latches where they lock into the car when closing the door. Shot some silicone in there (gonna follow up with something a bit more substantial soon), and the noise is instantly gone. Back seat rattle is still a mystery though.
 
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Old 05-10-2019, 11:32 AM
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Originally Posted by Magneu
Quick update for anyone that stumbles on this, turns out the creak noise was my door latches where they lock into the car when closing the door. Shot some silicone in there (gonna follow up with something a bit more substantial soon), and the noise is instantly gone. Back seat rattle is still a mystery though.
X brace under the rear passenger seats.
 
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Old 05-10-2019, 06:11 PM
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I just do what my wife has done for years. She cranks the volume on the radio up, until all noises are eliminated. I never hear her complain about car noises.
 
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Old 05-11-2019, 11:35 PM
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Originally Posted by Urbanengineer View Post
X brace under the rear passenger seats.
It's a coupe, so no brace for me. Pretty sure I've narrowed it down to the seat-belt turnaround located above the seat back. Only the passenger side rattles, so more investigating is required as to why.
 
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Old 05-12-2019, 08:01 AM
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Originally Posted by Mr.GEE View Post
I just do what my wife has done for years. She cranks the volume on the radio up, until all noises are eliminated. I never hear her complain about car noises.
Hahaha, I do that too and call it my Dolby noise reduction.
 

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