I think I will record the noise that it makes on start up tomorrow and take it to the dealership so the can listen to it
I have a 2009 sedan, and had the same type of noise. Your power train warranty is 5 years or 60,000 miles. When the engine is first started up, and the transmission placed into gear, the noise could easily be heard, and as the engine got up to operating temperature, the noise would lessen, but still could be heard. Took it back into the dealer, left it overnight, and did a cold start for the tech early the next morning with the temperature around 23 degrees. Tech heard the noise and diagnosed it as a piston slap, which I already surmised. The problem with a piston slap is that many engines can run for a good many miles, and outside of the noise give good service. In other cases, the piston slap will eventually lead to the engine using more oil, and eventually a total failure. In my case, I was still under warranty, and the dealership replaced the engine with a short block, and all is well.