I need radiator help

Just installed brand new radiator after a minor fender bender. Got all the hoses and clamps installed and was excited to fill up the system with coolant and warm it up. Unfortunately as soon as I added coolant the coolant poured directly out of the bottom as fast as gravity could pull it. I mean immediately upon adding coolant 0% remained in the system. I checked all my hoses and clamps and they are all perfectly sealed and dry. Is this a bad radiator? Please help!