Rattling Noise.

Hey everybody, I need a little help. I am getting a loud rattling noise from under the hood in the morning's when it is cold outside. It does it whenever it is cold outside and only does it at the first start up. Then as the truck starts to idle up the sound breaks up and goes away. Not sure what it is or if it is normal but figured someone may be able to help. Thanks!

I have the same noise in the winter but im down south so it doesnt happen till january or so. I cant really remember how it sounded i think mine sounded more like air bubbles and stuff?. Sounds like its around the radiator/intercooler area