New Exhaust - Warranty Repair

[Muscle Car Lover]

If you search the forum you can see a few members had an issue with the dual-mode exhaust and muffler packing material coming out and down the tailpipe. I looked in my pipe a while ago with a light and indeed saw some packing material making its way out.

I have been busy for a while with personal issues, but today I went for an oil change and had them document the issue. The service rep was great. He said they saw the material in the pipe AND one of the dual mode flaps was broken, I guess it was stuck closed.

They ordered me an entire new exhaust from the manifolds back and next week they will install it.

Issue resolved and a brand new dual mode exhaust, nice!

[foo.fighter]

wow thats wicked. Im having some problems with my dual mode now, the flaps kinda rattle... I got the switch to open and close em when i want, rattle only heard on start up... I got headers and hi flows so exhaust is too loud im sure there is rattle but youd never hear it driving around.

Anyway I showed the dealer and of course they wouldn't warranty it since i've changed the back pressure with my mods.. oh well =/

[Muscle Car Lover]

Originally Posted by foo.fighter

wow thats wicked. Im having some problems with my dual mode now, the flaps kinda rattle... I got the switch to open and close em when i want, rattle only heard on start up... I got headers and hi flows so exhaust is too loud im sure there is rattle but youd never hear it driving around.

Anyway I showed the dealer and of course they wouldn't warranty it since i've changed the back pressure with my mods.. oh well =/

Fighter,
I have already paid for substantial mods and installation (by the Legendary Slowhawk Performance) but my mother in law is terminal with cancer so it seems to me to be dumb hot rodding right now. I have to wait until spring.

That said, I wanted to get the new exhaust BEFORE the mods as my car is still under warranty. Maybe it all worked out.

[FrostySS]

I've had a few of them come back with that flap rattling.

[Muscle Car Lover]

Work completed today, entire new dual mode exhaust from the manifolds back. Great warranty repair and service.

[FrostySS]

Originally Posted by Muscle Car Lover

Work completed today, entire new dual mode exhaust from the manifolds back. Great warranty repair and service.

If you get a survey from GM make sure you give them all "completely satisfied" and 10 answers.

[Kendall421]

I had the same rattle with my NPP...sounds like gravel rattling around in the muffler when you rev and let it decel at idle. It got progressively worse. Dealer could not figure it out so they replaced the whole system. Upon start up of new system...still rattled, but a little less. I accepted it and drove it all summer...it now rattles just like the first one does. I have adjusted the NPP rods to keep tension on the gates. I also have the switch and when you flip the switch you can actually here THE rattle noise as the flaps seat! With it on the lift, the mechanic and I held the flaps halfway open and reved the motor...same noise exists! So we don't think it is the flaps. Only thing we can come up with is that the noise is coming from the mufflers or even up stream further and the noise just comes out the pipes like a blow horn! LOL They said they could replace the whole system again under warranty, but we listened to others on the lot and they have the same sound. So I have accepted that the noise is just what it is. I still think it is something in the flaps. But an entire new system did not fix mine.

[Kendall421]

Originally Posted by FrostySS

I've had a few of them come back with that flap rattling.

So was there a way to adjust so the rattle went away? If you replaced them completely, did the new systems always fix the problem?
My dealer completely replaced my NPP...cat back and the problem did not go away. I can tell you that the rattle is definitely on the drivers side. When it was on the lift and the mechanic hit the gas, I stood at each corner and the rattle was very evident on the drivers side, but not so much on the passengers side.

[Muscle Car Lover]

Originally Posted by Kendall421

So was there a way to adjust so the rattle went away? If you replaced them completely, did the new systems always fix the problem?
My dealer completely replaced my NPP...cat back and the problem did not go away. I can tell you that the rattle is definitely on the drivers side. When it was on the lift and the mechanic hit the gas, I stood at each corner and the rattle was very evident on the drivers side, but not so much on the passengers side.

Sorry you are still having issues. Can you see any muffler packing material inside the pipes from the back? Use a flash light and look way up the bend. Mine sounds 100% better but will monitor it to see if issue comes back.