so my 93 civic has been a nothing but a problem for me for the last 2 weeks. first it blows cold air when i turn on the heater and over heated. so i replace the thremostat and it worked for a day and back to cold air blowing on heater. then i replace the radiator and it worked fine for little bit then it started over heating again. so i am stuck now. could it be the water pump? or the head gasket going bad? thanks for all the help guys.

 

it might be the head gasket.... thats wat happen to my boys car....

 

Is your coolant level dropping?
Are you properly bleeding the system each time you refill it?

If the water pump is going bad you will usually see coolant weeping from it. If your headgasket is leaking, you might have white clouds of smoke on startup sometimes and/or grey sludge on your dipstick/oilcap. I say might as headgasket signs can vary substantially.
With that said, there is a good chance that you just have air in the system somewhere.

 

It's a bad water pump. The propeller shaft is probably worn out. Usually when you have air in the system, you'd still get hot heat.