today i was out driving and coolant started leaking out somewhere towards the back of the block, and then inside the car on the passenger side underneath where the heating unit is. there was also a bunch of smoke coming out of all the vents.

any ideas, is there a seal or something that could have burst or did something break under the dash in the heating unit?

 

Sounds like a blown heater hose.

 

would that be under the dash where it goes through the firewall?

 

It could also be the heater core. If you end up taking it all apart I would replace the heater core too unless it is almost new.