some owner had hot problems, to remove air
from system put the front end of car up on jack stands, heater valve open to allow coolant to flow through the heater core pushing air out,idle motor w/ cap off.After t/stat has has been open a few minutes then your done.If you see a constant supply of air bubbles that can indicate head gasket problem.
With the rad cap off & the fluid level low, look inside the rad at the tubes to see if small debris has collected in the tube opening= clogging the radiator.The debris became dislodge from the inner passages of the block & head. Frustrating after having the rad cleaned out.
Was the block drain plug removed (exhaust side @ # 4 cyl area) to flushed out the engine.