There is a leak in the radiator.
Hello. It may very well be that there is a leak in the radiator, but it is also possible that there is a leak in another area of the coolant system. All of the radiator hoses, as well as the hoses in the coolant system, should be inspected to pinpoint exactly where the leak is and if there are multiple. A certified technician can perform a coolant system check in order to find where the leak is coming from and make the appropriate fixes.