Why is antifreeze leaking from a metal tube that come from inside the truck?

I just resently changed the water pump and when I turn on the truck it was fine, the i let it sit for a while and all of the sudden the antifreeze started dripping from a metal tube that comes from the inside of the truck and now all of my antifreeze is gone, and when i turn the ac, smoke comes from the vents and it smells like boiling antifreeze.How can I fix this prblem?