As the title says, between 1 and 2 RPM, I can hear a noise sounding like chains hitting the ground or a broken fan spinning while rubbing against something like metal against metal. The noise is noticeable if you pay attention to it. You cant hear it with the windows up, at least not yet. All this noise is coming from the engine. My car is a 2003 Audi A4 1.8T with 66k miles on it.

What is this noise? Its really bugging me I want to get it fixed.