what could be wrong with my car as it keeps over heating? on 2005 Toyota Avalon

i have replaced the coolant bottle as was cracked. have flushed the system replaced the thermostat and put in new coolant. while doing this i also replaced the oil filter drained all the old oil and put in new oil. there is no oil in coolant or smoke blowing from exhaust so isnt the head gasket. could it possibly be the water pump?

Asked by for the 2005 Toyota Avalon
pressure test coolant sys,check belt,belt tension and pullys replace rad cap if its an open system. elect test all temp gauges,relays,switches including fan motors