My car heats up fast even though I changed thermostat. Instead of hot air, it's cold. What's going on?

Please Help! I have a Dodge 2002 and it's been so much trouble recently. I drove from TN to CA and as soon as I got to LA, I had to LITERALLY stop every 2-3 miles to cool off my car. Before driving in a long distance, I changed thermostat. I had to stop because the heating arrow will go all the way up. I'd take off thermostat and let it cool off then put it back. Radiator guys told me there was an air when I was changing thermostat so they did smt. I was afraid my accumulator is starting to mess up and my car is useless, but they said it's fine. My air conditioner was working perfectly for about 2 weeks until the arrow went back up again. Does anybody know what's going on? That would suck if I have to replace my waterpump cause it's so pricey
My car heats up fast even though I changed thermostat. Instead of hot air, it's cold. What's going on?
CHECK THE FAN, IT MIGHT NOT BE WORKING PROPERLY
My car heats up fast even though I changed thermostat. Instead of hot air, it's cold. What's going on?
did you drill a little hole in the thermostat before it was installed? This keeps the air from getting trapped where coolant SHOULD be.

http://www.mgfcar.de/thermostat/Dcp_5568鈥?/a>

also make sure your antifreeze is mixed 50/50 with water!



when the heater blows cold, that means there isnt enough water in the system.
There is a thermostat which regulates the flow of coolant, and then there is a temperature sensor. See if you can find/replace that, it may be giving false readings.

If there's air in your coolant system, leave that cap off that you're not supposed to take off when the engine is hot and run it with that open till it stops bubbling. (if there is air in your system however, you would get %26quot;bubbles%26quot; where your engine temp would rise at a swift rate and then return to normal after a little while)

Has the level of coolant been going down? If it hasn't then your water pump is likely fine, they tend to leak when they go.

Otherwise I'd say maybe it's a head gasket?

And check to see that the fan is working first of course.