Purchased in 2014 used. Exhaust was quet/normal. Some time in 2015 it began to make a noise on start up but it would go away in 15 to 30 seconds. I asked a friend that works for GM to see what he could tell me about it. He said it was normal. Yeah, there is a video on Youtube that shows in writing to do nothing about it. Dummy me, believed him. At this time the car was still under new warranty. As time went by the noise got louder and began to manifest itself at some odd rpms.

So, I finally took it to the dealership. They thought at first it was the catalytic converter under the car and it was under warranty. A day or so later said it was not the cat/conv but was the "Y" pipe that went from the engines two catalytic converters to the exhaust pipe connection at the rear of the engine. They told me that the engine had to be jacked up to get the thing off (4 hrs to remove it on the mech. books). Cost was approx. $750 and that was giving me a break on the parts price and some labor. I declined to do the repair due to approximately $3700 in bills being due in the next three months. The car sounds like a race car when I start it now. Loud!