Just had it start to leak coolant. The radiator was steaming hot, and the leak was from the overfill tank. Ran the heat just to keep the temp down to get it home. (Temp gauge started going up until I turned on the heat (in the summer) and blasted it. This seemed to help keep the temp down and no more coolant overflow.
Garage tested the radiator and found no leaks. They replaced the thermostat.
Is there any chance this is the sign of the water pump (original) starting to go? I'll be keeping my eyes on the temp gauge over the coming days. I hope the thermostat does the trick, but is this a sign of other issues?
I'm not hearing any noises, but I'm concerned about the potential of this being the start of the end of the water pump.