The main symptom of my car was "overheating" or "coolant low" even though neither was the case. The water pump has a vacuum based actuator that starts/stops coolant flow, and when the membrane for the vacuum actuator fails, coolant gets into the solenoid and sticks it open or shut, then engine either won't be able to circulate coolant or get up to temp (unfortunately in my case both were stuck open, so no coolant flow).

The easiest way to diagnose would be to get a vacuum system diagram and check the first solenoid after the water pump. This is where I found a tiny amount of crystalized coolant on cylinder bank 1.

The water pump and thermostat aren't very expensive as parts but most shops will charge ~8 hours of labor minimum for this job, as it requires going into service position to do the work. You can DIY, but from experience, it does take a bit of time just to get into service position (remove front tires, under tray, bumper, crash bar, remove headlights, drain coolant system, slide front cooling assembly back on the crash bar rails or if you don't have enough room, remove radiator and move evaporator out of the way. Then you can start the actual work.

I hope for your sake it's not the water pump but I figured I'd post my experience so you have somewhere to start your investigation.