Got around to taking things apart last night. The first video below shows the spray around the engine bay, and then the noise from the pump. The second video is the pump removed. The plastic impeller disk is still intact, it feels like a bearing or something within the pump is grinding. I'm not sure what caused the failure, maybe a seal or something? No idea, but I'm relieved to not find bits of plastic everywhere. Coolant drained from the block was clean. Water pump pulley is caked with shit. Belts are ok but replacing them anyway.
Ordered new water pump, gasket, bolts, thermostat, pulley, belts... Already had the coolant at least!
new pump won't be here until the weekend I think
Water pump pulley not looking so hot