1st Method

Start the engine and keep the engine running at idle for 2 minutes.
Step on the accelerator pedal and hold it steady at 4500 rpm with the shift lever in N position to warm up the engine until the temperature of the engine coolant reaches 80°C.
Keep the engine running at 2500~3000 rpm in the N position for 15 minutes.

Fig 1: Engine Coolant Temperature Timing Chart (1st Method)

Courtesy of KIA MOTORS AMERICA, INC.