What could be causing this AC problem?

[Pretender]

I just installed an air conditioner (about 8 yrs old) in my room which I got from my dad, and when I turn it on, it makes a strange rattling noise inside. The noise gets louder if i turn it up higher, the noise is higher on fan mode than on cool mode, and (obviously) the noise stops when I turn it off. I dunno if it's normal or not since I haven't had an AC in my room since I was much younger. Any advice?

 

[Nick Stone]

You should be able to take off the front grill pretty easily with a screw driver. Then you can run it and see what's rattling around. The electrical connections should be protected so that you don't touch them. Might be the fan rubbing on a shroud. Should be pretty easy to bend or duct tape down whatever it is. If the fan motor bearing is going out -- then look for a way to grease it.