My coolant tank is leaking at the bottom should this be happening

 

Maybe you need to solder?

 

Its plastic.
The overflow is into the outer ring under 5he cap, once it gets into this ring it flows down a tibe & out under the tank.
So yes, its supposed to do that.
But find out why, because it should t do that.
Has the coolant system had the air bled out of it.?