I would say no to using a sealant because the core has only very fine spaces for the water to flow through, perhaps not as fine as in the earlier ‘honeycomb’ core radiators, but still needing care. A couple of years ago local section member Len Zitman gave me a can of a radiator sealant that claims to not restrict water flow within the core. It might be worth a try… It is called CT1 Miracle Seal, and it is made by C-Tec NI Ltd., in Northern Ireland. http://www.ct1ltd.com
Brian
