Mine I making the same noise. The water pump was replaced last summer. This sound was coming more from the other side of the engine. We replaced the pulley but the noise continues. It is worse with the AC on. With a stethoscope probe, the mechanic deduced the tensioner is not keeping it tight. Only thing is he couldn't find one to install. I saw a thread mentioned later years didn't have a tensioner. Any suggestions on where to find one or replacing it with a later model?