Highplains

My car was built almost exactly the same time. It has made the noise since the day we picked it up and, like yours, has gotten no worse, no better. You can best hear it with light acceleration and as it passes through the 1500 RPM range, rattles or warbles or whatever. It comes and goes. No other effect. No felt vibration or interruption in performance. The dealer's demonstrator did the same thing. Have close to 3000 miles on it at this point. Dealer turned off all the exhaust valves with a computer and it still did it. They checked underneath and could find nothing loose. I've run it in every mode with and without a Range device that turns off the ability to switch to 4 cylinders. Its an annoyance that I want fixed but I'm not worried about.

Strake

What you're describing is exactly what we're experiencing too. I've tried monitoring it in V4 or V8 and it makes no difference. I have spent some time underneath ours when jacked up in the garage and can't find any obvious things that might have been rubbing, etc. Only does it with a light load, gentle acceleration, steady foot ON the gas pedal. Remove my foot and coast, and it goes away. Like you, I've tried every combination of exhaust setting, mode setting, etc and it doesn't matter, still does it. I am certain, it sounds like I only hear it from my left ear and that it's coming from behind me, not the engine bay.

If you have contact with GM Techs, please pass along that it's not just your car, several others are known to exhibit this too.

thanks,

C7NOW

Just picked up a 2016 A8 NPP about 2 weeks ago and less than 120 miles so far and I can hear this slight I guess "warble" sound from the rear. Started hearing this after 50 miles on the car and exist on all modes. It typically happens when coasting between 30 - 40 mph and adding light gas, but goes away when easing off the accelerator, it's not loud but can pick up this distinctive noise in cabin.

Doesn't seem to be bearing as the sound goes away, haven't really notice if its getting worse or not but wanted to post to capture any update from this thread. Had a friend with a 2016 A8 non-NPP ride and mentioned it seem to be the AFM or NPP valve when going from V8 to V4.

Ed Ramberger

I am looking for any insight. I have a 2016 A8 non-Z51. At 350 miles (following break in procedures to the letter) I started hearing a whirring or a wooo wooo wooo or a warble noise from behind me. Until then I was really varying speeds so it may have been there since day one. It's at 1500 rpm, light throttle, 74mph in 8D or 8M. I can duplicate it at exactly 1500 rpm in 7th, 6th & 5th at lower speeds as long as I hit the RPM and light load. Exhaust modes do not change it, suspension modes do not change it, and it can be heard over the radio and the I captured it on my PDR in cabin mic with rpm overlay.

The perfect storm is a slight incline, very light throttle, 1500 rpm 8th gear and BINGO there it is. Then do the same in 7th at 1500 and you can get it again. On flat roads, it goes through it kind of quick, but it's falling dead square at the range I cruise at. Coming home from visiting family this weekend, I was sitting right at that range going crazy trying to determine what it was.


Pulling the NPP fuse did not change anything. Because it is rpm and not speed related, I do not believe it is differential fluid. When a diff bearing makes noise, it may whine/growl at a certain speed range or get louder with speed, but because it is RPM related and happens in several gears, that should take the tires, drive shafts to wheels and diff out of the mix. Anything on the output side of the transmission is turning at different speeds in every gear at 1500 rpm while the noise appears in multiple gears at the same rpm.

I can get onboard with a resonance as the cause but am unwilling to accept that a 70K car should have a resonance at a speed that many people drive at that can overcome the radio.

People have had transmissions and differentials replaced and the noise stays. I can't believe GM isn't aware, and I can't believe these premier car owners have to resort to searching forums. COME ON GM help us out here.

I am going to get this documented, and I believe that more and more people will begin to complain until GM must release a fix.

I was really hoping for exhaust valve opening because that fix is as easy as GM changing the timing of the event in a flash update.

I am convinced it's in the exhaust. Dealer unsure. I work with guys from NASCAR and other engine techs and they all swear its exhaust resonation. I can hear it over the radio. The more I search the more threads on different forums with the same complaints show up. Here is a link to the thread in stingray forums.

http://www.stingrayforums.com/forum/...ut-please.html

Ed Ramberger

How can I reach a GM Customer support person on the forum?

bjones7131

Look at the stickey for customer service tracking, open it up and click on it and send them a message explaining your problem. Get your problem documented, there is strength in numbers. Push for resolution.

bjones7131

My car was built in march, 2016

bjones7131

Guys I would suggest each of you contact GM customer support and complain and get your problem documented so we can get some attention to this problem. Thanks

KWC6

I have the exact situation as you describe. Dealer said it was caused by the NPP exhaust valves opening and closing bla bla bla.. Nothing to worry about but just an annoying sound.

bjones7131

I don't buy that because I have tried all the stuff to make sure the valves are open and still get the noise. Generate a customer service ticket to get it on record and they will contact your dealer to help with a resolution. I am sure not everyones NPP sounds like this or are we just unlucky.

Highplains

As I stated previously, my dealer had the tech turn off the valves by means of a laptop and it still did made the noise.

Strake

OK, I just posted a note to the Chevy Customer Service on the "Tracking" thread asking that they get this to their Tech Group for assistance.

I hope everyone else will join in too.....

Highplains

Strake:
Just posted a note there as well. Hopefully others will follow.

bjones7131

Good deal, i just got a call from my dealer to bring my car in to see if they can figure out my problem and got a PM from customer support indicating the had contacted my dealer. My reply to them was please get gm eng. involved so they can find the problem and eng. A fix. The problem is not my dealer they will fix the problem if they know what to fix. Thanks for raising the issue to cust. Support.

Highplains

Hope they have an answer that I can pass on to my dealer. Keep the forum posted.

Strake

Congrats on the progress ! Please pass along that there are numerous others with the same issue, if you talk with GM again. Hopefully, I will hear from GM Customer Service too.

VY427

My car has a noise similar to the one mentioned in this thread, but a little different. I'd describe it as a gear whine type sound, a moan or a noise somehow related to rotation. However, it could be a resonance of some sort, I suppose. It certainly seems rpm related. At times, I can also feel a slight vibration throughout the car, mostly in the shifter/center console area.

The noise can happen anywhere in the 1200-2500 rpm range under light-medium throttle (most commonly at 1500-1800 rpm, though). It makes the noise while accelerating or decelerating. Clutch in or out makes no difference. It goes away with added throttle/rpm. It will also make the noise if I rev the engine in neutral.

Can any of you hear this noise at a stop while revving the engine in neutral to the target rpm range?

Strake

no weird noise while stopped and revving engine. Also, NO vibration and really tight on the rpm range.... Very close to 1500. If you are experiencing the same issue, you are the first with the M7 trans that I've seen. I believe everyone else has the A8 who has experienced this. I've never had the noise while decelerating, braking or coasting....... just light, steady acceleration.

Highplains

See Strakes answer which has the same symptoms as mine.

VY427

Thanks for the quick reply, fellas. Strange thing is, the noise goes away almost completely after driving the car for a little while. It's crazy. The dealer couldn't pinpoint the source or find anything obviously wrong and claimed that a new Stingray they had in stock made a similar noise. No way this is a normal noise. My car didn't do it for the first 2K miles or so of use.