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Old 02-05-2013, 08:58 PM   #1
sswiss3000's Avatar
Drives: 2012 Camaro 2SS Vert, L99
Join Date: Sep 2011
Location: Dekalb IL
Posts: 360
Convertible Exhaust Butterfly Valve - Service Bulletin

Convertible Exhaust Baffle - Bulletin

So I just came back from the dealership after dropping of my 2012 convertible 2SS (L99) for some warranty work as well as an issue I had with a squeaky noise coming from the back of the car.

Long story short they informed me that it was caused by a butterfly valve that was in the exhaust pipe right between the resonator and the muffler. This valve only exists on the L99s (convertibles only) in order to reduce exhaust noise during idle or low RPM operation (AFM). The service manager will give me the bulletin number tomorrow so that I can poste it. Basically it’s a valve that is held shut with a small spring and will only open during high exhaust flow situation. Thus the quick squeaky noise whenever I hit the gas

I was surprised to hear that the Automatic convertibles have such a valve installed, as I personally have never read or heard anything about it till now.
Has anyone ever removed this valve? Would be interested to hear the exhaust sound difference and how bad the AFM sound would be

update: My dealership told me that this noise is normal after all!! I have a hard time believing that

"The 2011 Camaro Convertible SS equipped with the 6.2L engine (RPO L99) and the 6-speed automatic transmission (RPO MX0) may have a metallic or spring-type rattle noise that is usually heard at idle when parked next to a wall or when pulling into or out of a garage.
The exhaust system for the 2011 model year has been revised to reduce exhaust noises heard during Active Fuel Management (AFM) mode. This revision includes a spring-loaded valve placed in the exhaust system before the muffler"
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Last edited by sswiss3000; 04-06-2016 at 08:18 PM.
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