V6 NPP hissing/buzzing exhaust - dealer refusing to fix

ben8 · 09-14-2022, 08:13 PM

Hey guys,

A few days ago, the exhaust on my camaro 2021 v6 (12k miles) started giving a hissing or buzzing sound when accelerating. The car is equipped with factory NPP.

The issue is not intermittent, it happens continuously after you do one hard acceleration. Then, whenever you press gas pedal, above about 2K RPM, it's giving this annoying sound.

Here's a recording - https://www.youtube.com/shorts/9aYWDva6Nw0
I hope you can clearly hear this sort of metallic buzzing.

The dealer refused to fix it. They said, they visually (lol) inspected the exhaust and all is good. My two questions are - What could this be? And how can I make the dealer take care of it?

ben8 · 09-18-2022, 07:08 PM

The buzzing has gotten worse since I posted - it now occurs not only during acceleration but also following acceleration. Here's the recording - https://youtu.be/FRERx-jIrJc

Does anyone have any idea? Would enormously appreciate any insight.

arpad_m · 09-18-2022, 09:59 PM

Try these two easily DIYable fixes, they helped with my car:

TSB 16-NA-003
TSB 18-NA-172

ben8 · 09-18-2022, 10:30 PM

Thank you, arpad.

I actually followed the first one some time ago, TSB 16-NA-003, as there was a squeak coming from the valves, and it did help with that issue. I'll look into the second bulletin soon. BTW, the dealer checked heat shields and also confirmed there were no leaks. I'll report back on how this develops.

easttxss · 09-22-2022, 01:42 PM

I got my car used and it already had the exhaust system on it. I could only hear the noise my left actuator was making if the car was in accessory mode (key on/engine off). It sounded like a really noisy fuel pump running. Had a neighbor, who is a dealer tech, bring his laptop home and do a relearn on it and that fixed the problem. Not sure if that is the same issue that you are having or not. If the dealer hasn't tried a simple relearn, you might want to try a different dealer.

09-14-2022, 08:13 PM	#1
ben8 Drives: Camaro lt1 Join Date: Mar 2022 Location: Pennsylvania Posts: 11	V6 NPP hissing/buzzing exhaust - dealer refusing to fix Hey guys, A few days ago, the exhaust on my camaro 2021 v6 (12k miles) started giving a hissing or buzzing sound when accelerating. The car is equipped with factory NPP. The issue is not intermittent, it happens continuously after you do one hard acceleration. Then, whenever you press gas pedal, above about 2K RPM, it's giving this annoying sound. Here's a recording - https://www.youtube.com/shorts/9aYWDva6Nw0 I hope you can clearly hear this sort of metallic buzzing. The dealer refused to fix it. They said, they visually (lol) inspected the exhaust and all is good. My two questions are - What could this be? And how can I make the dealer take care of it?

09-18-2022, 09:59 PM	#3
arpad_m Drives: 2018 Camaro 2SS A8 Join Date: Jul 2017 Location: East Tennessee Posts: 11,576 View My Garage	Try these two easily DIYable fixes, they helped with my car: TSB 16-NA-003 TSB 18-NA-172 __________________ 2018 Camaro 2SS — G7E MX0 NPP F55 IO6 735 rwhp \| 665 rwtq Magnuson TVS 2300 80mm pulley \| Kooks 1 7/8" LT headers \| JRE smooth idle terminator cam \| LT4 FS & injectors \| TSP forged pistons & rods JMS PowerMAX \| DSX flex fuel kit \| Roto-Fab CAI \| Soler 95mm LT5 TB \| 1LE wheels \| 1LE brakes \| BMR rear cradle lockout \| JRE custom tune 1100 - 1/30/18 \| 2000 - 1/31/18 3000 - 2/06/18 TPW 2/26/18 3400 - 2/19/18 \| 3800 - 2/26/18 4300 - 2/27/18 \| 4B00 - 3/01/18 4200 - 3/05/18 \| 4800 - 3/14/18 5000 - 3/16/18 \| 6000 - 3/19/18

09-18-2022, 10:30 PM	#4
ben8 Drives: Camaro lt1 Join Date: Mar 2022 Location: Pennsylvania Posts: 11	Thank you, arpad. I actually followed the first one some time ago, TSB 16-NA-003, as there was a squeak coming from the valves, and it did help with that issue. I'll look into the second bulletin soon. BTW, the dealer checked heat shields and also confirmed there were no leaks. I'll report back on how this develops. Last edited by ben8; 09-19-2022 at 03:14 AM.

09-22-2022, 01:42 PM	#5
easttxss Drives: '16 2SS M6 Join Date: Aug 2019 Location: Hughes Springs, TX Posts: 319	I got my car used and it already had the exhaust system on it. I could only hear the noise my left actuator was making if the car was in accessory mode (key on/engine off). It sounded like a really noisy fuel pump running. Had a neighbor, who is a dealer tech, bring his laptop home and do a relearn on it and that fixed the problem. Not sure if that is the same issue that you are having or not. If the dealer hasn't tried a simple relearn, you might want to try a different dealer. __________________ David '16 2SS M6 black on black, SW long tube full exhaust, NPP, Roto-fab CAI, ported stock TB '16 2SS M6 black w/Metallic black stripes, Kalahari, 6 piston front (totaled 1/22/20) '14 Fusion Titanium 2.0T '83 Jeep Wagoneer

09-18-2022, 07:08 PM	#2
ben8 Drives: Camaro lt1 Join Date: Mar 2022 Location: Pennsylvania Posts: 11	The buzzing has gotten worse since I posted - it now occurs not only during acceleration but also following acceleration. Here's the recording - https://youtu.be/FRERx-jIrJc Does anyone have any idea? Would enormously appreciate any insight.

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