Did a search but only found a vague mention to something similar so I thought I'd post to see if anyone has experience this and knows of a fix...

I have a 2005 6MT Coupe with around 31k miles on it. When the A/C is on, I hear an annoying metallic rattle coming from the engine compartment. It goes away if I turn the AC off. I tried to isolate the noise last time I was doing an oil change but no luck (I didn't have a hose handy).

Anyone have any suggestions on what it might be? I'll try to get a garden hose to sniff around some more when I get a chance but hopefully someone has already dealt with this and will save me the trouble.

Thanks!