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The Rattling Sounds of the Cadillac CTS-V Supercharger [w/ video]

Juan Barnett August 1, 2012 Cars You Should Know, Featured 57 Comments

[Please welcome Juan Barnett to the Redusernab. You may have heard Juan’s name, and his website , mentioned here before. Juan will be a part-time contributor to the Hoon, much like the rest of us are.]

When the Cadillac CTS-V first came out I knew I wanted one right away. 556hp, great handling, room for four, large trunk, a perfect dad car if you look past the gas mileage. And the price. And the chrome grill, which I painted black right away. There is one more downside to owning the CTS-V however – the noise – and not the good kind of noise. I’ve come to terms that to own the ‘fastest sedan in the world’ I would have to endure a sound that can only be described as a can full of marbles, being tossed-about under the hood.

Many CTS-V owners have experienced this issue which resulted in General Motors releasing a Technical Service Bulletin (TSB: PIP4523A) which basically states: the rattle is normal, take your $73,000 car and live with it.

CTS-V owners, like most performance vehicle owners, are very active online. Owners took to the forums to discuss and share their displeasure with ‘the rattle’.  They made enough noise that in November of 2009, it prompted Ed Piatek then Program Engineering Manager on the CTS-V to step in and clarify a few facts. Below is the response Ed provided to members of CadillacForums.com:

Photo: Carguydad.com/Kamil Kaluski from .

I’m Ed Piatek and I’m the Program Engineering Manager on the CTS-V. I recognize that this forum represents the thoughts and experiences of some very passionate owners and enthusiasts, and appropriately many of us on the engineering team periodically review this and other forums to keep our finger on the pulse of this important group.

While we cannot respond or comment on every post or question, the number of comments and degree of inaccurate information around supercharger shaft wear merits an engineering response to set the record straight, and assuage any concerns of our V series owners. Here is the response from our engine experts:

The torsional isolator is used in the CTSv LSA engine to isolate potential gear rattle noise during idle. The isolator contains a torsional spring that fits over the shaft. Purpose of the shaft is to distribute the stresses in the torsional spring. As the spring goes thru its travel, the inside of the coils can the shaft. The spring material is intentionally harder than the shaft which by design results in visual witness marks and/or limited wear on the shaft. The witness marks and/or limited wear is expected and has been observed on all the Eaton component durability tests, GM engine and vehicle durability tests and on customer vehicles with no impact on the functionality of the spring and isolator. The shaft and isolator are in a sealed cavity, separate from the rest of the supercharger and engine.

Q: Will this shaft wear harm my engine?

A: No. The visible wear will not damage the engine. The supercharger and the engine were tested and successfully validated to meet all GM durability requirements…which are much more severe than any customer usage.

Q: What causes this wear?

A: The isolator contains a torsional spring that fits over the shaft. The purpose of the shaft is to better distribute the stresses in the torsional spring and prolong its life. As the spring goes thru its travel, the inside of the coils can the shaft. The spring is a harder material than the shaft…so that when there is , the spring will not potentially break. If the spring breaks, then the torsional isolator function is lost.

The following pictures show in detail the wear described above by the Cadillac engineers and was provided by member Heavy H2O of CadillacForums.com:

In the picture above the GM isolator is the one on the left and the community-sourced isolator (aka ‘The Fix‘) is on the right.

DIY to the Rescue

In an effort to resolve the problem, CTS-V owners created their own fix – installing a solid isolator without the abrasive metal spring inside. And whatta ya know – silence! (or as silent as a supercharged 6.2 liter can be). This also means the shaft is no longer being disintegrated.

Why didn’t GM address this issue earlier? It could be because the supercharger is sourced directly from Eaton assembled. As I was told by a GM service tech, “we are prohibited from taking apart that supercharger.”

It’s also important to note that many service managers have explained to customers that any further damage to the supercharger could not be covered under warranty, if the owner opened up the supercharger and installed a non-GM part. Like the solid isolator above.

Enter the new LSA

In a post by user smackdownCTSV of , he pointed out that according to a diagram of the 2012 LSA on GM’s media page the new LSA will no longer have the internal spring in the supercharger isolator (See below).

Did the engineers have an epiphany? Or did they come to the same conclusion that the rest of the CTS-V community did – uhh…that sound ain’t NORMAL.

A representative from Cadillac Customer Service provided the following back in the forum discussion:

If this is a widespread concern, I am happy to document it for further consideration by my superiors. I am unfamiliar with this forum as I am filling in for Katie until Wednesday; are there other threads regarding the supercharger rattle you’ve described here? What model year(s) is this prevalent in? I would like, if you all are interested, to document your username(s) if you own a CTS-V with this concern.

Cadillac Customer Service

While Cadillac seems interested in this issue now, the bigger question will be if GM is willing to issue a TSB for repair/replacement of a part that isn’t a safety issue. If what the service advisers have told me is true, about not being able to repair the supercharger, GM will be required to recall the entire supercharger rather than issuing a TSB for a new isolator…which could be the very reason the General has been mum on the issue from the start.

Either way, GM or the supercharger supplier, need to come up with a solution and make this right. Either allow GM service technicians to install a new isolator or recall the entire unit. Link to the thread on Cadillac Forums: 

The Service Bulletin:

On July 25, 2012 GM did issue Service Bulletin: #PIP4523E (Document ID: 2891501) which revised the original Service Bulletin: PIP4523A by including newer models (2013 CTS-V and 2013 ZR-1). In summary the document states that any “marble type noise” or “sounds similar to combustion noises of a diesel engine” are “normal.”

This bulletin does not offer a solution to the rattle, which occurs only at idle or low rpm. The bulletins says to check for noise at 1200rpm and basically states the lower RPM noise is normal, without really saying it.

Video of the rattle sound: 

I recorded an iPhone video of the sound coming from the CTS-V. You’ll notice I’m not “near a wall” nor do I “have the hood open.” It’s important to note that this video was of a cold engine. The metallic racket worsens once the car is at full operating temperate. Should a sub-$70,000 super-sedan sound this way?


  • TurboNarwhal

    Almost sounds as bad as when my Buick's 3800SC needed a new coupler.

    • cyrekzz

      yep – 98 gtp – replaced the coupler with a new one – green from ZZperformance! rattle gone

  • guest

    and people argued on jalopnik that GM was better than mazda…

    • Welcome. We don't argue much here and we'd like to keep it that way. We think RX-7s are reliable and make the right sounds.

      • Here's to us, and people like us.

        • Speak for yourself. I can't stand people like us.

    • Scandinavian Flick

      What's a "jalopnik"?

      • Etymology to the rescue! It looks to be a somewhat clumsy portmanteau word from "jalopy" and "apparatchik" so it presumably refers to something that was once a source of pride but is now thoroughly worn out, well past its prime, yet remains entrenched as a loyal, unimaginative cog within a large, powerful, possibly sinister organization.

        Am I close?

        • Scandinavian Flick

          Wow, that makes much more sense than what I was thinking. I just figured it was similar to something I stepped in earlier. I guess I can stop telling people that the smell is jalopnik on my shoe.

        • mr. mzs zsm msz esq

          Jalopy possibly comes from Ancient Aztek originally and apparat (the base of the Russian) from Latin apparatus via German loan word. I was surprised, more so you did not work in the Latin. Your etymology was wonderful though! There is a connotation of person involved in what you described as well due to the -chik and -nik suffixes.

        • pj134

          This is glorious.

    • akismet-c77e523b23f7c7b40face0d0e8ebbcd2

      Exactly. Couple this with the airbags going off during spirited driving, and you can see why people still stay away from GM products.

  • Ha! That's why I am careful to only buy vehicles that are not covered by a warranty. That way when something goes wrong, I have no one to tell me I can't do what's needed to fix it…or help me fix it…or pay for fixing it…

    wait, um…nevermind.

    • I was with you up to the second paragraph.

  • "Witness marks." great euphemism.

    "Officer, that's not a burn-out. Those black streaks are just 'witness marks' from my tires ing the pavement."

    • Mental note: Save this comment for next visit with constabulary.

  • Joe_Btfsplk

    My Kubota tractor sounds just like that, but only when it's cold….

  • Manic_King

    Metal from that shaft which gets "eaten" by that spring ends up where? Some room left so metal flakes can accumulate there?

    • joshuman

      Exactly. Before I got to the photos I thought maybe these witness marks resembled scratches or something that would not produce much in the way of metal sawdust. But, man, that torsional isolator shaft looks like a used dog toy.

    • Juan Barnett

      A few people have posted photos of the debris that builds up from the metal shavings. There is a fear that this could end up hurting the supercharger in the long run, but GM doesn't seem interested in that. Hence the 2013's being equipped w/ the same parts.

  • smalleyxb122

    That makes the “normal” piston slap from my LS2 not sound so bad. I will agree with the official GM statement insomuch as it likely won’t affect the longevity of the engine or the supercharger, but I will certainly agree with the owners’ stance that it shouldn’t be making such a racket, and with the remedy being so relatively simple, it’s a shame that there might legitimately be some contractual obligation with Eaton preventing GM from offering said remedy to the owners.

    The bigger concern that I see is this “normal” noise potentially masking the onset of more troublesome conditions. If your car always sounds like it’s developing a rod knock, how will you know when it develops a rod knock?

  • I've been disheartened to hear about the issues that CTS-V owners have been having. A buddy of mine bought a lightly used one (thankfully under warranty) and he has had the car in the shop several times for issues with the throttle body and rear differential, IIRC. A CTS-V wagon is still at the top of my lotto-winning car purchase list, but it's not fun hearing your superhero has several Achille's Heels.

    Like the post above said, the Eaton superchargers in lots of 3800SC GM cars had similar issues when the coupler failed, and the fix is an aftermarket urethane piece. Of course, those cars are long out of warranty, so there's no problem with the dealer.

    • Juan Barnett

      I've had the car for a year. In that year I've had a few things replaced. Things that I couldn't replace: the panoramic roof – when you turn or 'flex' the body it squeaks like like a fat guy walking across wooden floors in an 80 year old house. The Recaros also have a rocking issue. In hard turns they rock up off their mounts and rub the center console. Yes. The racing seats designed to take 1G turns move. This was recalled as well I believe.

      There are a few design issues. Take the panoramic sunshade. When you have the windows down and the shade closed, it flaps like a sail caught in a trade wind. Slapping away at the glass making a horrible racket. The cord GM sells you for the iPod is only 2.5 inches long. You can't get to the iPod once you plug it in. Its under your elbow basically.

      I don't want to sound like a grumpy old man, which would be fitting for a Caddy, but I had high hopes for this car. Having owned 3 C6 Corvettes, I thought this was the perfect solution to my budding family needs. Sadly I was mistaken.

      Jeep SRT, nice to meet you. My name is Juan.

      • Scandinavian Flick

        Your first paragraph indicates a scary amount of chassis flex… Which is surprising for a car that is that heavy, yet handles as well as it does. As I have not really looked into it, I wonder if there are aftermarket suppliers of chassis braces that might help…

        Either that, or just seam weld the entire yacht.

        • Juan Barnett

          I'll mount up a GoPro next time I'm out in it. It makes enough sounds you could probably remix it into some sort of V8 Dubstep

          • Scandinavian Flick

            CTS-V remix by Skrillex


            Vroom Vroom WZEEEEE,
            Vroom ZEEEEEE,
            Brooom room BZZZZEEEEE wreeeeeeeek
            CHAT CHAT CHAT
            WEEEEEE Vroom vroom

            • Devin

              I once described Skrillex as the sound of an industrial carpet cleaner going through a particularly nasty thick shag.

              • Spot on. I'd heard OF Skrillex, but hadn't actually heard anything he contaminated "worked" on until a buddy's 13 y.o. son played something for us one day when we were shooting the shit about music.

                Our loss.

        • HTWHLS

          I had this debate about seam welding…and a few body men/chassis men said that it wasn't really going to change anything and while I appreciated their back, I still (in my admittedly non-engineering-trained mind) think it would help. I've been going back and forth on this and would appreciate the hoons here helping out.

          • sub frame connectors?

    • JayP2112

      The MkI CTS-V was on my shortlist until I did a little research. The rear end issues scared me away.

      And the 6 lug wheels… what was that about???

  • So this is a spring in a coupler to do what? Seems like added complexity for a problem that isn't there.

    • Juan Barnett

      The way it was explained to me was that the spring was to prevent 'blower whine' and 'any reverberations that result from the spinning shaft." What does it really do? Eats shaft.

      • Scandinavian Flick

        Why would you want to prevent blower whine? People are weird…

        Btw, welcome, and thanks for the article. It was an interesting read.

        • TX_Stig

          I agree, what's up with preventing blower whine? I thought's that was the other primary purpose of a supercharger. That's like people putting aftermarket pipes on a motorcycle but not wanting the wonderful popping sound on throttle overrun. Bunch of weenies…

      • jeepjeff

        Wait, they installed a part to reduce noise that causes horrible low-rpm my-engine-is-going-to-implode sounds, and it eats the shaft?


        • Scandinavian Flick

          It muffles down low while eating the shaft…

          …I'll leave now…

          • jeepjeff

            No, no, you can stay.

            Wait… Uh… Maybe that didn't come out right…

            • jeepjeff

              I must have scared him off.

              <img src=";

          • mr. mzs zsm msz esq

            Eat-on blower indeed.

      • Also, welcome to the 'Verse. I liked the read and the depth was very good.

    • Adds lightness, slowly.

  • OA5599

    This seems like the perfect opportunity to upgrade the supercharger through Lingenfelter, Hennessey, or one of the others. Then you get their warranty on the blower and GM's on whatever wasn't part of the upgrade package. Eliminate the noise and get more horsepower to boot.

    • But S/C upgrade kits usually consist of pulleys. Also, one shouldn't have to upgrade anything on a $70,000 in order to fix what shouldn't have been broken.

  • JayP2112

    They're just biding time until these cars are out of warranty and they don't have to deal with thousands of costly rebuilds.

    The Tremec 3650 was intro'd with the 2001 Cobra and Bullitt. My Bullitt wouldn't shift into 3th if I was running thru the gears semi hard. Even cruising, the thing was hard to shift. This made DE's impossible (and don't bark, others who DD their cars had the problem too). Brought it up to the dealer. Couldn't replicate the problem (Really????!!!?) and lived with the suck-azz transmission.

    In 2004, I wrecked the car and sold it. Not 4 months later, there was a TSB on the transmissions and by that time, the 3 year warranty was up on most of the 2001 models.

    EDIT: Like everything else I do, I didn't learn my lesson. My 2005 has the remote shift 3650. Still, it's worlds better than that Chinese built Getrag MT82!

  • Mad_Hungarian

    Next time someone tells you GM has changed, go back and read that TSB..

  • topdeadcentre

    Are these the sounds of the CTS-V ownership experience?
    <img src=";

    • They need to come out with a Don Martin Edition.

      • Love Don Martin. Too bad his name doesn't mean much to most not already in Cadillac's demographic. (Or are a shitload of <40 y.o. dudes reading old Mad magazines?)

  • dukeisduke

    It sounds to me like this is also a battle between GM and Eaton, with Eaton telling GM, "Tell your customers to shut up. We're not fixing anything, and oh, BTW, your technicians better keep their grimy fingers out of our superchargers."

    • Juan Barnett

      Whats great is that GM has known about this since 09 and continues to put the same unit in vehicles. I haven't yet confirmed that the isolator is in the Camaro (which is where the diagram was pulled) but GM's own bulletin says the 13 ZR1s and CTS-Vs are included.

  • charles darnall

    Ed Piatek was at the Cadillac Performance Academy on 30 Nov and made no mention of the rattle now on evident on my new V coupe.
    Sounds like marbles and it stated at 220 miles. Now 340, service managers at the dealer claim not to know to the torsional spring problem.

  • Joe

    My '09 CTS-V developed a high frequency whine coming from the engine compartment. At first it only happened occasionally and when the engine was cold and car was outside in 20-30 degree weather. I thought it was the belt tensioner pully/mechanism. Then one cool, but not cold, mid-morning after cranking the big dog up remotely and walking up to it the high frequency, now screaming, noise was back. Immediately took it to dealer and told them what I thought it could be. Next day they called and said no, it was a bearing in the supercharger and they were going to replace the supercharger – love saying and typing that word, by the way. Well, a week and a half later I pick it up on Monday (they had to back order the supercharger), 18 Feb. Question, how do I check to insure I get the solid torsional spring isolator?

  • pcowens

    Dropped my 2009 CTS-V at the dealer in Sacramento on March 23, 2013. The mechanic said not to drive the car.. The supercharger was about to fail. Cadillac is trying to find a replacement supercharger but not having any luck. This is crazy. Thankfully I purchased the extended warranty.. The car has 97k freeway miles so I'm assuming others may fail around that time..

  • Ohio Owner

    Just took mine in yesterday for the same problem on my 2013 CTSV. Dealer is replacing the entire supercharger, so I am not sure as of this writing if GM had Eaton resolve this problem altogether. I'll find out more from the dealer and post what they advise me on this warranty repair. Sad thing is my car only has 19,000 miles on it, and seeing a major repair like this really makes me wonder what GM is trying to do with all these superchargers having similar issues and costs associated to it. As one posted commented; agree that GM is is just trying to by time and get all these cars out of warranty so you and I have to pick up the bill to replace. I wonder what the Corvette Stingray is using for the supercharger on this car and if it is similar to the one being used in the Cadillac. It Sure would blemish the performance of these cars if they just slapped this supercharger on without involving Eaton to fix this problem before they roll out the new models. What a shame!!!

    • Lugnut42

      Did you ever get anything from the dealer about how others could get theirs fixed? My dealer is saying there is no TSB regarding this issue and that it is normal.

  • Bill Strait

    Fighting the BATTLE right now with Autonation in West Palm Beach..they say normal. Passengers say WTF is wrong with your car???
    2014 V not included in the bulletin, same noise.

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