How do I know if my water pump is going bad?

Warning signs: 1) Coolant drip under the car after driving (check front of engine for pink/green trails). 2) Whining or grinding noise from the front of the engine that changes with RPM. 3) Coolant level slowly dropping with no visible external leaks. 4) The weep hole on the pump body is wet — this is a built-in early warning that the shaft seal is failing. On the 3.2L Pentastar, the water pump is external and belt-driven, so replacement is reasonable (2-3 hours, ~ part). Not like the Chrysler 3.6L where it's internal.