Why is overflow tank still going to empty after radiator was fixed. No leaks

When the car is cooled off, check the lvl in the radiator. It may be covered with some plastic bits you gotta take off for access. If its low then top off ur overflow and ur radiator. Need to check ur engine oil lvl also... If whats on the dipstick is a milky whitish color, ur coolant is leaking into ur engine. Not good.