At present there are no replacement radiators available from LnR.
However, it is pretty easy build your own. Just go to one of the home improvement stores and purchase some 18 gauge wire. Measure your current radiator and each of the stubs, then measure the distance from the matchbox to where each stub connects to the main radiator. Go to the auto parts store and buy the connectors and place them the same distance from the matchbox as your Quad.
73 for now,