2005 Civic problem

My sister got a new civic couple of weeks ago. Everytime we drive more than 5 minutes and then stop and shut off the car. I can hear this ding ding ding metal sound around the engine/ muffler area. It will start to slow down and then stop when the engine get cold. This sound is exactly the same sound I heard in my old car. I know that there is nothing wrong w/ the civic. But I was wondering why it will happen to a brand new car. Can I fix this problem myself? Can I call up the dealership and ask them to fix it or will they ignore me for such small issue.