Thread Sealant for Coolant Parts?

One of those things.
I stay away from RTV even though that is everyone's '"go to."
Hey, it's cheap and every auto parts store has it.
Why not?
But as I have recommend before when it has come up, try this.
It was designed by Rolls Royce for aviation.
It works as a gasket dressing and for sealing those pesky exhaust fasteners on the water jacket

Read about it and try it.
Or not.
And no worries about pieces of it comming off and getting in a system.