I don't think Silicone is your best choice.... I suggest you do your own testing before you choose but I can tell you back in the 70's a buddy had a radiator hose fail while traveling from Las Vegas to San Diego... & while he had access to water to fill the radiator the only thing he had to attempt to repair the hose with was Super Glue.... He tried it & it worked so well it didn't leak a drop... He wound up picking up a replacement hose but left that hose in place for nearly six months just kinda as a test to see how well it would hold up...