There is no return tank or even a flange, just a hole in the neck where it should be. My boss said it's a mystery as none ever hits the ground but plain as day, it pushes out the hole and from there is evenly distributed all over the radiator and back section of the compartment. I believe it is quite confused as the water is being moved by the impellor which is supposed to be a fan and the water pump impellor is acting as a fan pushing air around inside.

@ edward t. Just like the toosie roll pop ads of long ago......The world may never know.

didja figure out where the coolant went?

Thankyou, I replaced the master cylinder today and checked the cooling system and warwa there was nothing in the radiator. It would have taken me some time to figure it to be causing the freezing issue as I have zero experience with natural gas applications.

check the engine coolant, it is used to warm up the regulator, check flow into and out of regulator, if all good, you have a bad regulator as it is leaking.
it is 'almost normal' to see some cooling (to the touch) of the external regulator just before the thermostat fully opens, in some trucks with restrictive water flow hoses to the regulator.