Personally I use non-hardening Permatex#1, the old stand-by black goop in the tube. In this case you need something that resists both antifreeze
If you want a laugh, go to google
and input “ sealant on freeze plugs”. You’ll get the whole gamut of answers, from dry installation
to silicon to permatex to paint
to Indian Head
shellac, and everyone says they are successful.
So there ya go.....