1993 Ford Ranger

The leak is not from the overflow container. It is coming from a tube located outside the cab above the liner of the fenderwell and appears to be coming from the heater unit located under the hood. There is no coolant leaking inside the cab. The "tube" looks like it should have a hose on it, but there is not one there. The coolant comes out of the "tube". It is difficult to describe the location because I am not familiar with the jargon. I just cannot figure why I had no issue until I filled the coolant overflow container. I cannot figure a connection between filling the container and experiencing this escape pf coolant. I removed the container and inspected, no leaks. The radiator is not losing coolant and the engine does not overheat. Thanks for your help.

Windshield does fog, but the only loss of coolant seems to be from the overflow container which has no leaks. I would think that I would lose all of my coolant rather quickly?