Tapered is another term for NPT. They say use sealant on tapered, but I get your meaning, should seal. I don't believe it was sealed and there was no sign of a leak. But I think I'll hit it with high temp. sealant.
OT: I suppose temperature senders are tapered as well? I installed that one dry, though I read something about a grease that's conductive friendly.
Thanks for the good info.
https://www.industrialspec.com/about...tandards-intro