Q:

Can I use a weapon that makes noise when there's no room for more noise tokens? 

Is it possible to use a weapon making noise if there's no more room for noise tokens on a location?  And is it possible to use a weapon making noise in the colony, knowing that you can't put noise token on the colony? 

A:

Read the description on the weapon cards.  Most of them doesn't make noise.  Ones that do, have a clause: "add noise if possible".  Thus, you don't add noise in the colony or if 4 noise tokens are already present at the location.