I just got a 2007 Caliber. I hear water running inside the dash as I start up the car, mostly first thing in the morning. I am told this is water running around some coil? I have always had Hondas and have never heard water running inside the dash. Second, I get a musty smell coming from the vents. This car does not have 3000 miles. I do not know what to do since two mechanics say they do not smell the mold.
Chances are the drain for the AC is plugged and not allowing the condensation to exit the vehicle properly. As a result, you get that smell.
As far as the noise you hear at start up, make sure the coolant is full. What you are hearing is coolant entering the heater core. It should remain full all of the time and not be heard unless it's low on coolant.