Ford Repair: 2004 Freestar, going on a trip, freestar

Question
I have a 2004 Freestar that is getting a clicking noise coming from the belt area at low RPM, when I give it a little gas the noise goes away.  Stting in traffic the other day a guy driving next to me told me it was a water pump bearing.  I just had it to a mechanic who said everything looked ok for the trip that we are currently on.
Do you think that could be the problem, if so what are my choices?  If the pump stops working before I get it to a mechanic am I at risk of loosing my engine or causing other major damage?

Answer
I do agree with the guy in the traffic light, usually water pump bearing with some noise then it goes at once.

Now you mentioned that the mechanic said it was ok, is the noise still there?  If it is, then it is not ok.

My recommendation is to have it checked as it could be the pump or belt that it is about to go.  Especially since you're going on a trip, once the water pump go, the car will overheat, and will not be drivable.  Modern engine control do have limiter that will stop the engine once it gets too hot.