According to a report from The Car Connection, GM has discovered a problem with the superchargers of the 6.2-liter V8s found in the Chevrolet Camaro ZL1 and the Cadillac CTS-V. Apparently, the issue rests around the internal bearing shaft grease, which can become contaminated (we aren't sure with what). If left unchecked, it'll first lead to a rattle at idle, which goes away under slight throttle. The real warning stage is when a high-pitched squeal develops, signaling that the bearing shaft has failed. Naturally, severe engine damage is the next step (although it's possible that the engine will also just refuse to turnover, although neither case is desirable).
According to TCC, GM will replace the superchargers on vehicles that have exhibited symptoms of bearing shaft failure free of charge. It will also, allegedly, be extending the warranty on all supercharged ZL1s and CTS-Vs to 10 years or 120,000 miles (whichever comes first), from the date of purchase. Officially, only 2009 to 2013 CTS-Vs and 2012 to 2013 ZL1s are suffering from this issue.
It's important to note that we've seen nothing from the National Highway Traffic Safety Administration regarding a recall, while GM's media website is devoid of any information on the supercharger troubles.
We have, of course, reached out to General Motors and will be sure to update this story when more information becomes available.