What is confusing to me is that there was good water discharge for the first 30 seconds, then it slowed to near nothing….
Usually it is the other way around, little or no spray on start up, then it sprays for a bit when the thermostat opens up…
I wouldn’t bother with the temperature gage…You might want to unplug the wiring from the hot light, then hook the leads up to a "hot horn" from a newer engine….