Several things can contribute to this, however since you have recently replaced the radiator:
Ensure ALL the air has been bled out of the coolant system, there is a 10mm hex head bolt near the front of the plenum for this purpose.
You did not mention if the water pump was replaced, as per the manual this should be done every 100,000 km at the same time as the CAM belt.
If you have access to diagnostic software and equipment for this car check the O2 sensor, if this is faulty your engine may run lean to 'compensate' for a bad reading, the leaner the fuel mix the hotter it will get.