I noticed when i start my Micra in the wet/cold after it has been sitting all night or after work, it makes a rattling sound. This only happens when it is wet or cold outside and it only does it when it sits. I guess if the car is warm is doesnt do anything. Its a slight rattle with minimal shakes. It only starts when i put it in drive for a couple of seconds. Can anybody tell me why? is is worth bringing it in to the dealer under warranty or are they just going to say im crazy?

Let me know what i should do or if anybody has this problem.