Cam chain rattles when cold

[Speed_imp]

Today y picked up my bike from the dealer and the service manager told me there's no sound. Then I asked for a written copy of the inform (the bike is under warranty) but then in the copy it says that "the timing chain is making some noise but it is within the tolerance. Come back when the sound is worse or louder". At the garage where I work I have retracted the tensioner an let it go again automatically to see if it was somehow stuck. Tomorrow when the bike is cold let's see...