It will cause a mess, but it’s the best way to drain the system. Once the system is done draining, remove the main upper and lower coolant hoses connected to the radiator.

Hey, this car has a brand-new radiator! Then I noticed that the radiator in this car was in perfect, brand-new condition. The most likely scenario for this is that the car had a blown head gasket ...

Most cars will have a drain plug at the bottom of the radiator, but some do not. In that case, it is best to remove the lower radiator hose.