Need help with my sunfire, coolant leak

Last night i bought a 96 sunfire, its a 2.2L with a stick. it drove fine from the guys house for about 30 miles, i noticed the temp slowly kept going up, and the heat was starting to get extremely hot. then I came to a stop light and the car died. I started it back up and it started smoking. It is leaking coolant right out of the bottom of the coolant resivoir, some kind of breather or something is under there.

It has leaked a lot of coolant out this morning when I was going to leave work, and theres no heat, just cold air. Could this be because of a frozen line somewhere? its been very cold and the guy said it hasnt been run for a few days before I got it. I really need help to get this figured out, my car is sitting at my work still because I dont want to drive it. It doesnt leak out the motor, just poors out the bottom of the resivoir. Any ideas?

thanks

You have a blown head gasket. There was no heat the next time cause there was air in the system from it dumping out.

Could be a blown head gasket (the smoking and dying would suggest that)... but I'd replace the reservoir first... there's an air purge hose (the top, small one) and a coolant supply hose (the bottom, big one). if the bottom of the reservoir is cracked, you'll be dumping coolant out as fast as the air bleed hose can dump it out, gradually losing coolant will make the temperature rise as the coolant gets lower. And let that be a lesson, after you look over the car, have your mechanic look over the car, and then ask the owner if you can take it on a very long test drive. Not to accuse anyone of anything, but almost any problem can be fixed for a few dozen miles at almost no cost.