November 11, 2020 at 8:54 am #626862
Since I got the car in late July, there is a popping sound under the hood during normal to moderate acceleration at lower speeds (under 50). No noise at idle or reved up in park. No noise can be heard at constant speeds. I don’t know what the problem is but think it might be the turbo wastegates. The frequency of the popping increases with engine speed under load, so it seems to be tied to the rpms of the engine. It sort of sounds like clack-clack-clack. Hard to describe. It is not related to engine temperature. Also, if you had the radio on and could not hear this noise, you wouldn’t know anything is wrong. Performance is excellent! Gas mileage is not, though. Around 14. My usual dealer’s service manager took a drive with me and said that it is “normal” for a turbo, but conveniently didn’t have another car on the lot to compare it to. He said that the GM field engineer also says it is normal. It is not normal! After 3 visits to this dealer and 3 loaner cars (in the shop for 21 days total), I went to a second dealer today (I am in southwest Florida). Their service manager clearly heard it during the test drive. He had another low mileage CT5-V on the lot. It has 2,000 miles and mine has 1,100. He drove both and said that the sound from my car was NOT heard on the other car. But, he really is not sure of what is causing it. So, I have another loaner car and am hoping that they can finally find the source of the problem. I just wanted to get this out there in case others have this problem or someone can point me in the right direction. I am considering the lemon law as a last resort.
November 11, 2020 at 1:20 pm #626937
Just a short follow-up to my original post. The noise actually sounds more like distant automatic assault weapons fire. Pop-Pop-Pop.
January 2, 2021 at 7:44 am #634159
My question: is your CT5 an 8-speed or 10-speed transmission? The reason I ask is because I also got a CT5 in late July and noticed a sound coming from under the car. I first noticed it at constant slow speed. It continued until the speed changed from either increasing or decreasing the speed. Once I was aware of the sound (more like a helicopter sound, or flapping sound) I was able to hear it at speeds under 60. I took it into the dealer, and the tech was able to hear the sound. He contacted GM engineering. First, they thought it was the plastic shield under the car, so they sent insulation, that didn’t fix it. Next a CT5 on the West Coast had the same sound; it had a bad electronic motor mount. They checked mine which also had the same problem. They replaced it, but that didn’t fix the sound. They then said it was a transmission problem and needed to write new software to fix. I waited but then was told that it was a CHARACTERISTIC of all CT4s and CT5s with a 10-speed transmission. No further action was to be taken on their part.
If nothing else happens, I will be contacting legal advice, as to pursuing The Florida Lemon Law or The Magnuson Moss Warranty Act.
February 9, 2021 at 3:33 pm #639647
So. This is one of those situations where we say people should really understand the mission of the car they are buying, because car companies tune a car to match its mission. In the case of the CT5-V is that of a performance car, and as Car and Driver’s recent lightning lap testing shows, the CT5-V turns out to be a legit performance car.
Sure, it’s a luxury performance car, but it is a performance car. It’s not just the CT5 with the most non-Blackwing horsepower. The engine and all of it’s constituent parts are supposed to perform and behave like such parts for a performance car. For a CT5 with a V-6 where everything is tuned to feel and sound more like a luxury vehicle, see the CT5-550T.
It has the same engine but detuned a bit on power and is meant to sound more like a car wit a more traditional luxury while still being sporty.
While a traditional luxury car’s engine is meant to be more composed and —- if you will —- gentlemanly in its behavior, a performance luxury car like the CT5-V an engine is designed to sound a bit more like a bad boy instead of a gentleman.
That pop-pop-pop you hear under harder acceleration is considered desirable in a performance car. This just basically just means your engine is tuned more for performance and fun aural amusement than an engine tuned for more exclusively luxury use. In other words, this is a feature not a bug.
There are performance car fans who would be very jealous of you when yo drive by and your engine begins to crackle and pop like that. Performance car guys who can’t afford a CT5-V who hear you going by while that engine makes that popping sound probably thinks “why can’t I be more like that guy?”
But if an engine acting like a naughty boy displeases you see if your dealer will let you trade it for a 550T whose engine still sounds great and sporty, but is a bit better mannered under hard acceleration.
Failing that, you can use the My Mode to set your steering, brakes, suspension, and engine to perform the way you want them to. Put everything in sport except the engine. There is either a tour mode or stealth mode for your V-6 engine that would alter the exhaust manifolds to make your engine behave a bit more prim and proper if that’s what you desire.
Or leave everything as is, and know that performance and sports car junkies know you got a cool sounding car.
February 9, 2021 at 4:54 pm #639653
I appreciate the time that you have taken to respond to my posting. I am a car enthusiast and this is not my first turbo. I know all about the sounds associated with turbos, like blowoff valves and wastegates. I can even play with the exhaust noise it generates. This is not a normal sound. If you read my original post you will see that the service manager at the second dealer I went to agreed that the sound is abnormal. The field service engineer came twice and tried two things that did not fix the problem. He then took audio recordings to bring back to GM for further review. (My car has been at the dealer since December 3rd.) Following the audio recordings, the engineer had the right turbo replaced. No change. Then, they “borrowed” the entire exhaust system from another car and tried that. Nope. Finally they tried one last thing, which I am not privy to. No, again. Sooooo, GM has agreed to buy back my CT5-V and credit it toward a 2021 model with all of the same options. I was told, yesterday, that it is built and awaiting shipment. Not all noises coming from performance cars, like this one, are to be envied by others. Some noises, like this one, are actually embarrassing when people are next to you as you moderately accelerate from a stop light. I am very pleased to know that GM (Cadillac) is doing the right thing here. I have been a GM guy all of my life starting with my ’67 LeMans. I will continue to be a GM guy. So, what is a 73 year old guy doing with a velocity red CT5-V? Simple answer. I can’t get into a Corvette much less get out of one.
February 10, 2021 at 2:04 am #639669
Well, I misunderstood what you were describing. Almost every video review of the CT5-V you will notice that you can hear a crackle and pop sound under more enthusiastic acceleration. . That sound not only sounds normal but intentionally tuned into the engine in V-Series configuration —- doesn’t sound the same or is not as accentuated in 550T configuration —- often desired (in fact in the reviews usually brings a grin, and happy commentary from the reviewer(s).
What you are saying here does make it sound like something different. Glad they are replacing the car for you. Frankly, while I appreciate performance cars like the V-Series and the sounds they can make, I am more of a 550T kind of guy (if, nothing else, for aesthetics).
The engine, in either guise (V or 550T) sounds great on video and in person, so hope your replacement car is all this engine can be.
February 10, 2021 at 7:33 am #639701
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