Question about my 1993 Honda Coolant System?

I ume the temp gauge reads normal i.e. in the center of its range. If you're lucky, you could just have some air trapped in the system. Have you bled the air out of the coolant? Why don't you fix the hole in the overflow tank at least temporarily with silicone or something, bleed the air out using the bleeder bolt, and see if the problem goes away. The tank comes out just by pulling straight up on it. If that doesn't fix it, then the "boiling" could be exhaust gas leaking into the coolant. You could have a blown head gasket, or worse a cracked block.