[speedup]

Took my 2017 to the dealer for the raspy/rattling NPP exhaust. They tried the epoxy "fix" which actually made the problem worse.

They told me that since the epoxy didn't work they would need GMs approval to replace the exhaust. They got the approval, and are replacing it this Wednesday.

Has anyone had this done at the dealer? Hopefully it fixed the issue?

[Beamz27]

Following...

[clrkmr]

I had it done. They did the epoxy fix and still had issues. They said it was valves further up in the exhaust (I think the active fuel valves??) and they are not serviceable. So replaced the entire exhaust. So far no issues (~6k miles since fix).

[Calcanuck]

I am trying to decide if I have this issue. When my car is cold it makes a high pitch sound that seems to go away when it warms up. I would describe it almost like a chirping sound. Is that what the NPP rattle sounds like?

[JaxChris]

Welcome to the club. The AFM exhaust valves after the secondary cats can also enter the rattle trap. When that happens, then will cut the exhaust just after the secondary and everything to the back will be new. Ask them to epoxy both pairs of the new valves before install (so they last longer) and also make sure they are careful with the alignment. The factory has a jig for lining up the exhaust front to rear, don't let them count on alignment based on the cuts of the tech that removed the old exhaust.

[speedup]

Originally Posted by Calcanuck

I am trying to decide if I have this issue. When my car is cold it makes a high pitch sound that seems to go away when it warms up. I would describe it almost like a chirping sound. Is that what the NPP rattle sounds like?

I first noticed mine when driving at cruising speeds between 20-70mph, when accelerating it would make an annoying ratting/raspy sound for a little bit. After they did the epoxy fix it would do it right when I started the car, as well as during acceleration.

On mine it sounded like it was coming primarily from the passenger side.

Check out this thread, it has the GM bulletin about it. https://www.camaro6.com/forums/showthread.php?t=456749

It's definitely annoying, so if you feel annoyed when you hear it, thats probably it lol.

[KingLT1]

Originally Posted by JaxChris

Welcome to the club. The AFM exhaust valves after the secondary cats can also enter the rattle trap. When that happens, then will cut the exhaust just after the secondary and everything to the back will be new. Ask them to epoxy both pairs of the new valves before install (so they last longer) and also make sure they are careful with the alignment. The factory has a jig for lining up the exhaust front to rear, don't let them count on alignment based on the cuts of the tech that removed the old exhaust.

why wouldn't they just replace the entire catback so nothing has to be cut?

[speedup]

Got my car back yesterday. They replaced the exhaust, and some other part they said they found rattling.

Parts listed on invoice:

8x 12626354 gaskets
1x 84314680 muffler
1x 12618338 fuel feed pipe

Feed pipe replacement said per bulletin # PIP5395D

Annoying rattle is finally gone!

[Magnum922]

Originally Posted by Calcanuck

I am trying to decide if I have this issue. When my car is cold it makes a high pitch sound that seems to go away when it warms up. I would describe it almost like a chirping sound. Is that what the NPP rattle sounds like?

Mine just started this morning. 2200 miles.