Odd engine noise issue
 

I’ve been a lurker for the longest time, and recently decided to join the family with a 2017 Camaro RS V6, with an A8. It’s been two weeks and I love the car. My wife and I both agree, it’s one of the best decisions we’ve made. However even after our acquisition I stayed lurking, and only a recently developing issue has prompted me to seek your expertise.
In the last week or so, I’ve been hearing this really odd engine noise. It is definitely a “groany” sound. And it seems to be related to speed, and RPM. I notice that when driving “efficiently”, I tend to hear it a lot. I’ve pinpointed the issue to a couple of things:

At lower speeds during city driving, I’ll hear an engine groan and rumble (almost sounds like a pickup truck) at around 1500 RPM. It is especially noticeable if up driving up a hill or something like that. I am talking about speeds around 60-76KM/Hour (35-46 MPH). At those speeds, the RPM is around 1500 only in higher gears and that when the noise comes on, at lower gears/higher RPM I don’t hear the grumble at all.

At higher speeds, during highway driving, I’ve heard it even at around 4000RPM. I’m talking about speeds of 120KM/Hour or more (75MPH), and once again at those speeds you only get 4000RPM or lower at the higher gears (6,7 and 8). Except at these speeds the groan is less rumbly, and more “boomy”. And once again, if I rev up the car towards red line, the sound disappears and I’m only left with the sweet sounding exhaust. Otherwise, I can clearly distinguish between the exhaust (with the sound coming from the rear) and the groan (coming from the front).

I read over the posts dealing with the rear differential groan issue. But I don’t think my issue is due to the rear differential for several reasons:

I hear the sound all the time, not only when the engine is cold.

I hear the sound in front of me, its not coming out of the rear.
The sound is not related to turning, its related to accelerating.

I’ve taken it to the dealership, and drove it around with the sales agent that sold me the car (very nice guy, I’ve been his customer for some years now). He heard it, but he couldn’t pin point if this is normal. He then connected me with the shop foreman. I’ve got an appointment with him in about 45 minutes. I’m hoping he can provide a clearer answer.

Has anyone here had this issue, or heard of this issue?

I thank you in advance for any help or guidance.

Do you have the NPP dual mode exhaust? It may just be the sound with the dampers open depending on how you have it set up, coupled with the drive mode you are in. In snow mode i find mine sounds a little truck like at the low rpm end but does not sound the same in tour or sport mode...more louder car like if that makes sense.

Thanks nftboy. No I don't have the NPP. And ironically my results are the opposite of yours. I hear it less in snow/ice mode, since it holds the gear longer. Definitely hear it the most in sports mode.

And update on my situation - took it to the dealership today and rode around with the shop foreman. He heard it. But told me the car hasn't been driven enough (866KM) and the adaptive transmission is trying to adjust to my driving style. I told him that cannot be causing this terrible sound. And so he said I should drive a little more, pass 1000km and if it doesn't get better then to bring it in the shop and they'll do a full diagnostic on it.

He also ruled out the rear differential as an issue.

Are you sure it isn't the direct injection? That can be quite noisy...

I'm not sure whether its the DI or not. But I can tell you that the sound is quite unpleasant, does not sound like the engine from the plethora of driving videos online, and I did not initially hear this sound when I picked up the car. And.....the volume of it has increased in the last few days.

I would check the rear end again, noise travels in funny ways sometimes. I had a rattle that I was sure was my dash against the frame at the base of the windshield. After using moving blankets to deaden sound I traced it to the rear seat on the passenger side at the shoulder belt level.

I get what I can only describe as like a plastic sounding, growl-like noise from the front of the car, consistently at 30 MPH anytime the car is cold and warming up; gear/RPM seem to be irrelevant, and it doesn't occur at any other speed. Once the car has warmed up, it goes away.

Cryssm- I think you should take it into the dealer. Your issue sounds like the rear diff. Mine is more of a metal like growl. The dealer has asked to bring in the vehicle and leave it for a few days. Will see where we get after that.

I have the RS 2LT V6 and I dont hear the noise youre describing. I do know going uphill(45mph) the car sounds like its growling in a good way(which I love) which im certain is normal.

Maybe next time you go for a drive and you hear the noise shoot a video and post it here maybe we can help?

Okay I took vet757's advice and did my best to record the sound. It's with my iPhone and iOS wouldn't let me upload it in HD, but the sound still comes out I think.

https://youtu.be/ch9WA3ygXwg

One thing I noticed while recording this, which I didn't before, is an engine noise while idling. Can anyone tell me if this is normal?
Anyway, I start accelerating and you'll hear the exhaust and engine sound the way it's supposed to. But then at higher gears when I try and go up the bridge you can clearly hear the groan.

Interested to hear what you guys think.

It was hard to hear for me. Can you point out what time in the video it starts?

Yeah the iPhone microphone isn't the greatest and so the volume is low. You gotta really turn it up or use headphones. Around 36 seconds while going up the bridge I press on the gas and you can hear the grumble.

Nah, I have that issue, also lol. I've already had the fluid changed, didn't help. Gonna contact my dealer soon about the issue persisting. The issue I cited above clearly comes from the front of the car.

As for your video, I heard the noise you're describing; it kind of sounds like the engine is just lugging at too low of an RPM. Nonetheless, it's definitely worth getting checked out (as you are).

That's what I thought at first. As a matter of fact that's what the dealer told me at first also. But it's loud, though it doesn't come out in the video. More importantly it'll happen at higher speeds on the highway, at higher RPMs. While at lower speeds it's a groan, at higher speeds it's sounds more "boomy".