92 525i, had a heating problem, replaced upper hose, fan clutch, and no coolant was circulating in the system, thought it was the thermostat, took off cover and there was no thermostat previous owner removed it. Thought it was the water pump, took off replaced it and still no coolant circulates through the cooling system without a thermostat installed. what can it be?
can it be the auxiliary water pump or what else?

Please reply!