Odd sound while accelerating

[Noxz]

Hi All,

I've done a search of the forums but haven't been able to find anything that seems to fit with the trouble I'm having.

I have a 2008 323i, and at low speeds, say around 20-30kph during moderate acceleration I hear this odd grinding/clicking sound coming from the car. I can't tell where its coming from but my guess is that its from under the hood (narrows it down so much..lol). I can only hear it when the windows are down and it doesn't happen all the time. Since I can't easily reproduce it I feel I will have a really hard time if/when I take it in to the repair shop.

Any thoughts/advise?

Thanks!
-Noxz