I have a 98 plymouth neon. A couple days ago I realized that I didn't have any heat in my car.. at all. Yesterday after lunch at work it started to overheat when I sitting still then it would cool down when I started to go. Then it started steaming. After work we decided to attempt to get it home. We only made it half way. All the way down the highway it was steaming and overheating hardcore. So today we changed the thermostat, and it still was steaming and over heating. The steam is coming out around the radiator cap. Then we changed the radiator cap, and it's still overheating. I can see antifreeze down near the cap. We have no idea where the leak is or what else could be wrong. Annnd I still don't have heat. Does anyone know what could be or what to do?
Thanks!

If you overheat these engines the head gasket will start leaking. It will pump air into the coolant and start blowing the coolant out of the cap. Also, because of the air bubbles, the water pump won't be able to circulate the water and...it will overheat. Because the water isn't circulating, you will have little or no heat from your heater. Time to take $800-$1200 out of your wallet and give it to your mechanic.

Does anyone know what could be or what to do?
Thanks!Your radiator may be clogged and/or bad. You changed the thermostat and radiator cap already, right? Are your cooling fans turning on? If not, check the fan relay to make sure it is good.