[goaterguy]

My car has been having the usual rear end noises like the popping and squeaking which seemed relatively normal for a 4 year old car with 55k miles.

On Sunday I returned from a business trip in Germany, when I travel my wife drives my car, and I noted a worse than usual rattling.

I decided to finally remove the spoiler and find out the source of the problems.

Well, after removing the spoiler (more on that later) I noted that the loop where the trunk latches was very loose, I could move it with my hand, tightening it solved the recent rattle but the spoiler was already off so I decided to give it a nice cleaning and fixing.

If you want to remove the spoiler, you will break some clips and retainers, some of them seem to be designed as sacrificial. I would order them in advance as you will leave holes exposed that will get water into the interior if it rains.
I broke 5 out of 6 11588882 clips (ordered all 6) Spoiler retainers
I also broke 1 24405740 clips (ordered 15 in bulk) Interior trim clips

You will need to remove the interior trim of the trunk as seen in some YouTube videos, remove the two screws from the handle and pull.

There are 7 10mm nuts and two torx screws in the corners. After removing all, the spoiler won't budge when pulled, there are 6 plastic retainers holding down the spoiler which you will have to break (at least I did).

You then will need to remove the broken retainers from the spoiler and the trunk. Some pieces will fall in between the hatch sheet-metal and rattle. I remove them using compressed air and they quickly blew out.

There was dirt and leaves under that spoiler that could probably be traced back to day one of use. Be careful when cleaning as water will get in the holes, I just used some wet rags that were so bad after, I just threw them away.

On some spots where the spoiler rubbed the hatch, I could see the primer and bare metal. I decided to spray three coats of PlastiDip to protect the bare metal and help with the vibrations. The spoiler has some weather stripes that are no longer pliable, I will likely replace them with silicone ones for durability and flexibility.

I'm running the car without spoiler until I receive the retainers and am surprised to say that I have zero noises in the back of the car.

 

[Steverino]

Thanks for the details, goaterguy. Pictures?

The spoiler can make a popping noise as it expands. Some have said it was due to accumulated grit/dirt/dust causing friction until the friction is overcome and the unit finally "pops" free with a noise. Others think the unit is simply prone to do this because it expands and contracts at a different rate than the metal it is mounted to.

Perhaps it is both and the cleaning you gave it plus the new flexible strip/gasket will reduce the expansion noise. Keep us updated please.

 

[goaterguy]

After knowing how the spoiler attaches to the car, I think the popping is due to one of the retainers that will set in and out of it's hole due to the heat expansion.

What pictures do you guys would like?

 

[LBV]

I've been having a weird noise like an acorn falling on the roof now and then. Very random (maybe once or twice a week) and I'm not going to take the spoiler apart because of it but glad to see others having it too. I wonder if GM has a TSB on it??

 

[Dutch]

I've been having a weird noise like an acorn falling on the roof now and then. Very random (maybe once or twice a week) and I'm not going to take the spoiler apart because of it but glad to see others having it too. I wonder if GM has a TSB on it??

Mine used to be a more muted "thump" but now it sounds like someone hit my car with a golf ball, it is sharp and loud and very startling and I need to get it fixed on my car!

 

[timoshev]

On my ex-'13 I had loud, startling thumps on trips which wee purported to be harmless fuel tank pressurization issues. Gen 2 is OK.

 

[Barry]

I've had the acorn thump sound on my 2013 a few times, but it doesn't happen very often. I think it is usually after being parked in the sun where it gets pretty hot.

My car is a light color. Not sure if that matters, but it might affect how hot the spoiler gets in the sun.

 

[Steverino]

What pictures do you guys would like?

Spoiler off, retainers, inside trim removed, the usual suspects, please.

 

[T-Keith]

I also have this sound on my 2014, plus regular squeaks. Interested in the pics and a solution to the popping. For my sqeuaks I think the spot weld is broken on one of the hinges and I'm thinking of trying to repair it.

 

[goaterguy]

Spoiler off, retainers, inside trim removed, the usual suspects, please.

After spraying plastidip

Here you can see the damage to the original paint

View attachment 154573




Trim clip: https://www.amazon.com/dp/B07BHDFXN...olid=2OCT68JW5P3FN&psc=0&ref_=lv_ov_lig_dp_it

Spoiler retainer: https://http2.mlstatic.com/clip-ret...s-D_NQ_NP_646727-MLA27047811001_032018-F.webp

 

[Dutch]

spoiler retainer link doesn't work for me

 

[Steverino]

spoiler retainer link doesn't work for me

Works in Chrome.

Thanks for the pics. Do you have one showing the underside of the spoiler?

 

[goaterguy]

Work done during the weekend. The retainers should arrive today as per USPS.
Right side details, note the weatherstripping, it's all caked up with dirt and brittle.

Left side details

All taped up

First light coat of plastidip to reduce tolerances
View attachment 154601
A few more coats

 

[goaterguy]

A few more pics:

All done with painting, now ready for the weatherstripping

Found this at Lowes for about $8. Good for about 3 spoilers

I added additional weatherstripping on a few places I thought it would help.
Pictures helped placing the weatherstripping in the original areas.

 

[Steverino]

Looks great. Hopefully the expansion/contraction 'pop' will be minimized or eliminated somewhere in this process.

 

[BlueEagleEV]

I've been hearing the loud popping sound like a rock hitting the rear window of my black 2014 for the last few years, starting the summer after I moved to Las Vegas. It typically happens within the first few minutes of driving, but I've heard it at other times, even when it was sitting in my garage before being driven. I don't think I've ever heard the sound more than once a day.

I've gotten used to it and don't really notice it any more unless I have passengers who react "What was that?!" I had thought about posting on here about it but didn't think such a vague description would be helpful. I finally decided to reach out today and happened to search the right keywords to get to this thread. If the culprit is heat expansion from the spoiler, it sure would be nice if GM puts out a fix!

 

[hellsop]

Heh. I just tumbled to that I haven't had the expansion pop since that fool hit my right rear passenger door with his Pilot back in April.

I wouldn't recommend that for a cure, though...

 

[Steverino]

I've been hearing the loud popping sound like a rock hitting the rear window of my black 2014 for the last few years, starting the summer after I moved to Las Vegas. It typically happens within the first few minutes of driving

Here in Chicago, I hear it in winter due to contraction when I pull the car out of the garage and the frigid air causes it to shrink a bit. Once and done, and not always. I do this some of it is trapped grit related. The grit induces some drag until it's overcome and that's when you hear the pop. That the OP's paint was rubbed off may support this hypothesis. Removal and cleaning may be the solution, though the OP went a bit further than that.

 

[JuneBug]

So far I've never heard the noise everyone here is describing. Maybe I don't spend enough time in my Volt, or maybe my hearing is as bad as my wife keeps telling me!

 

[Dutch]

So far I've never heard the noise everyone here is describing. Maybe I don't spend enough time in my Volt, or maybe my hearing is as bad as my wife keeps telling me!

IF YOU HAD THE THUMP...YOU'D KNOW! IT'S KIND OF HARD TO MISS! (shouting so you would be sure to hear me.....LOL)