Damn NPP Rattle!!!

Mac7504 · 03-24-2022, 05:34 PM

So I just picked up a new ZL1 March 5th and when I got her home and took her for a spin the next day and I noticed a slight rattle coming from the rear of the car. Not knowing this was "a thing", I overlooked it.

Now, after reading on it and realizing it's a known issue it's pissing me off. When I started the car today, I realize the sound was only prevalent on cold start then stops but upstream there is a smaller ping which I could live with tbh. It might be me just listening to closely to shit too, dunno.

After reviewing threads on here, there is a TSB for it but the date cuts off at 2019. Has anyone with a 2020+ have the dealer look at this and remove the dog ears to cure this?

At the end of the day, it's not a terrible issue but pisses me off that it's a known issue and GM couldn't be bothered to fix it.

I hate my OCD. lol

DWR · 03-24-2022, 06:15 PM

Remove the NPP fuse and enjoy ��, no idea if mine rattle or not lol

Mac7504 · 03-24-2022, 06:47 PM

Quote:

Originally Posted by DWR

Remove the NPP fuse and enjoy ��, no idea if mine rattle or not lol

Yeah I read about that and may do it, guess I would have to see how it sounds 100% open all the time. I don't want to be a dick to my neighbors should I need to leave early in the morning. That shouldn't be the fix though.

SATINSTEEL1LE · 03-24-2022, 06:57 PM

Quote:

Originally Posted by Mac7504

Yeah I read about that and may do it, guess I would have to see how it sounds 100% open all the time. I don't want to be a dick to my neighbors should I need to leave early in the morning. That shouldn't be the fix though.

It sounds awesome. No need for that fuse. Just put it in the center console and enjoy the exhaust.

raptor5244 · 03-24-2022, 06:57 PM

The NPP in my 2016 SS rattled. They were trying to fix it with epoxy and crap. Anyway, my 2021 ZL1 NPP doesn't seem to rattle but I pulled the fuse in the first week of ownership anyway. NPP isn't that loud IMO, just loud enough to know what you are driving.

DangerZL1 · 03-24-2022, 07:15 PM

What fuse # is the NPP? I think I need to pull it

LT4Greg · 03-24-2022, 07:55 PM

My 2017 ZL1 has a rattle too at idle but it doesn’t bother me so I say just drive and enjoy it. That supercharger whine will override the rattle and eventually you won’t notice it anymore.��

Mac7504 · 03-24-2022, 08:10 PM

Quote:

Originally Posted by DangerZL1

What fuse # is the NPP? I think I need to pull it

51 from what I've read.

Mac7504 · 03-24-2022, 08:13 PM

Quote:

Originally Posted by LT4Greg

My 2017 ZL1 has a rattle too at idle but it doesn’t bother me so I say just drive and enjoy it. That supercharger whine will override the rattle and eventually you won’t notice it anymore.��

It's not very loud but in track mode, and cold stars it's noticeable enough for me to be bothered, it stops after a bit so I don't notice while driving.

It's probably just in my head because I know it's an issue now. I may get over it. Lol

2SS Capt · 03-24-2022, 09:18 PM

Quote:

Originally Posted by DangerZL1

What fuse # is the NPP? I think I need to pull it

Quote:

Originally Posted by Mac7504

51 from what I've read.

I believe it is 51, mine has been out about a year and in my center console, if I need to put it back for whatever reason. It just gives me a bit more rumble while cruising than I would have had otherwise.

arpad_m · 03-24-2022, 09:22 PM

Quote:

Originally Posted by Mac7504

Yeah I read about that and may do it, guess I would have to see how it sounds 100% open all the time. I don't want to be a dick to my neighbors should I need to leave early in the morning. That shouldn't be the fix though.

You're right, the actual fix is in TSB 18-NA-172, however surprising this procedure is. I performed it myself and have had no rattle since then.

As far as maintenance goes, I spray the valves with Drislide every couple months to keep the hinge mechanism lubricated, as per TSB 16-NA-003.

Mac7504 · 03-24-2022, 09:24 PM

Quote:

Originally Posted by arpad_m

You're right, the actual fix is in TSB 18-NA-172, however surprising this procedure is. I performed it myself and have had no rattle since then.

As far as maintenance goes, I spray the valves with Drislide every couple months to keep the hinge mechanism lubricated, as per TSB 16-NA-003.

Yeah I'll pull it up again but that tsb stops at 2019. And while I hate going to the dealer service, I feel it's something they should fix.

I'll put up that tsb as well for maintenance, I wasn't aware of that so thank you for that.

arpad_m · 03-24-2022, 09:59 PM

Quote:

Originally Posted by Mac7504

Yeah I'll pull it up again but that tsb stops at 2019. And while I hate going to the dealer service, I feel it's something they should fix.

That might because it's a 2018 TSB, the latest MY was 2019 at that point.

I'm not 100% sure all past TSBs are properly updated with model year changes, and the actuator assembly itself doesn't seem to have changed, the exact same part came up for 2018 and 2021 in my searches.

Quote:

Originally Posted by Mac7504

I'll put up that tsb as well for maintenance, I wasn't aware of that so thank you for that.

But of course, you're welcome.

Mac7504 · 03-24-2022, 10:26 PM

Quote:

Originally Posted by arpad_m

That might because it's a 2018 TSB, the latest MY was 2019 at that point.

I'm not 100% sure all past TSBs are properly updated with model year changes, and the actuator assembly itself doesn't seem to have changed, the exact same part came up for 2018 and 2021 in my searches..

Very true, I didn't think that one thru. Haha The post I first realized this was an issue was in around 2018-19 so that makes sense..

Thanks again

03-24-2022, 05:34 PM	#1
Mac7504 Drives: 2003 Monte Carlo SS SLP, 2022 ZL1 Join Date: Aug 2021 Location: Los Angeles, CA Posts: 484	Damn NPP Rattle!!! So I just picked up a new ZL1 March 5th and when I got her home and took her for a spin the next day and I noticed a slight rattle coming from the rear of the car. Not knowing this was "a thing", I overlooked it. Now, after reading on it and realizing it's a known issue it's pissing me off. When I started the car today, I realize the sound was only prevalent on cold start then stops but upstream there is a smaller ping which I could live with tbh. It might be me just listening to closely to shit too, dunno. After reviewing threads on here, there is a TSB for it but the date cuts off at 2019. Has anyone with a 2020+ have the dealer look at this and remove the dog ears to cure this? At the end of the day, it's not a terrible issue but pisses me off that it's a known issue and GM couldn't be bothered to fix it. I hate my OCD. lol

03-24-2022, 06:57 PM	#5
raptor5244 Drives: 2022 CT4-V Blackwing Join Date: Sep 2013 Location: Florida Posts: 2,723	The NPP in my 2016 SS rattled. They were trying to fix it with epoxy and crap. Anyway, my 2021 ZL1 NPP doesn't seem to rattle but I pulled the fuse in the first week of ownership anyway. NPP isn't that loud IMO, just loud enough to know what you are driving. __________________ 2002 Corvette Z06 - Black - Sold 2013 Camaro SS 1LE - Black - M6 - Sold 2016 Camaro SS - Mosaic Black - A8 - Sold 2017 C7 Stingray - M7 Coupe - Sold 2019 C7 Grand Sport M7 Vert - Sold 2021 Camaro ZL1 - Black - A10 - Sold 2019 Tesla Model 3 2022 CT4-V Blackwing - M6

03-24-2022, 07:55 PM	#7
LT4Greg Drives: 2017 Camaro ZL1 Coupe Join Date: May 2016 Location: Georgia Posts: 5,813	My 2017 ZL1 has a rattle too at idle but it doesn’t bother me so I say just drive and enjoy it. That supercharger whine will override the rattle and eventually you won’t notice it anymore.�� __________________ ZL1 Coupe, PDR, Exposed carbon fiber hood insert, My Link with Nav, M6 6 speed and Silver Ice Metallic. Mods done: ceramic window tint, GM Accessories Camaro floor mats and Roto-Fab CAI.

03-24-2022, 07:15 PM	#6
DangerZL1 Drives: 2023 Black ZL1 Auto Join Date: Oct 2009 Location: FEMA Region 4 Posts: 2,935	What fuse # is the NPP? I think I need to pull it

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