Looking at a 16 year old thermostat

The continuing story of reviving this 1990 Volvo 740 that has been sitting for about 16 plus years. I am today going to do a radiator flush and take out all of the old coolant. I also want to remove the coolant from the engine block and I think this is the drain plug that is used to access and drain that coolant from the engine block itself.

Видео Looking at a 16 year old thermostat канала UsedFieroParts