Thread: Groaning/Grinding noise when hot

When the temperature outside is hot out, lets say, 80 degrees or above, my car has been making this strange sound coming from the engine. It sounds almost like a metal groaning/grinding sound. It is kind of hard to explain unless you hear it in person. It happens more noticeably the harder I push on the gas. It is the loudest from about 20-40 mph.

Once the temp cools down outside, the noise never occurs. What could be some possibilities for what is happening?

Edit: 2002 Grand Prix GT