2007 Chevy cobalt overheating

I had a similar problem, except it didn't progress to a leak. Nobody knew what was wrong with my car. I had to figure it out, and fix it on my own. It was an air pocket inside the engine block from "mechanics" not following the proper fluid filling instructions. Depending on where the leak is originating, you may or may not need a water pump. The excess pressure from overheating likely caused the leak, but it could be from one of the radiator hoses or even the drain plug on that side. The drain plug on the radiator doesn't completely empty the system, so it's a pretty useless feature. I bought myself a Chiltons Manual and stopped letting other people touch my car. I only seek help for things I don't have the equipment for, or lack the brute strength to do. 105lbs of angry female can still get a lot done on these things.