Hi everyone, my 2013 2.0tdi has a strange rattle that sounds a bit like a small ball bearing rolling around in the passenger side door bin.... the weird thing is it only does it on cold frosty mornings and it stops after exactly 3 miles, like clockwork. The engine is usually about 70degrees at that point. I’ve emptied everything from the cabin and checked for any loose trim. It’s louder when turning right and accelerating. Not present at idle. 
Any ideas? It’s really got me stumped. 

Maybe something to do with the blower motor? Have you checked if fan speed affects the noise?

Yeh I’ve turned off the climate control and it still does it. 
I’m not that bothered by the noise itself, I just don’t want it to be a sign of something expensive on the way out. 

I had the same  thing, I found that the air vents were making a lot of creaking (in my case) noises when cold, its interesting that when you think you know where the noise is its in a completely different area! . I have sprayed all the vents (where it rest against the dash) with a spray grease and know more noise. In fact I use spray grease for any creak and rattle and it works a treat.