What could be the main cause for my kia to overheat still?

What is your question?

My car has recently overheated on my way home from work one day, luckily i made it home just in time before it began to smoke. The cause was a busted radiator so i have replaced the radiator, radiator hose(both), thermostat, waterpump and timing belt. But even though i have replaced those things i can drive it around but as soon as i stop and let it idle for a bit it starts to overheat again. What else could be causing it to overheat?