I have a 1982 320i that is overheating. The engine temperature gauge will reach the maximum reading within a few minutes with the car idling. The thermostat has been replaced. The water pump is not leaking coolant. The cooling fan is belt driven and is functioning. The hoses from the engine to the radiator and to the thermostat housing are hot. The return hose from the radiator to the thermostat is cold. What are some test that can be performed to find out if the water pump is functioning? Could the radiator be clogged? The system has been flushed by someone else several times. The radiator has not been removed to be back flushed. The engine is indeed hot and I believe the sensor is reporting the correct temperature.