Sorry for reposting this but i really need help...Ok...I drive a 94 civic ex coupe with a GSR swap. About 2 weeks ago my car started over heating so i changed the thermostat. All was good for 2 weeks than today as i'm driving down the highway my car starts to overheat. Now my question is could it just be a coincidence the thermostat crapped out just after 2 weeks or is something deeper than that. I was thinking maybe the water pump?...Can that be it or something else?

 

When it over heats pop the hood and see if the fan is coming on.

 

Should be more then enough airflow through rad on the highway to keep engine coolant at normal temp., in fact enough for thermostat to close.
Replace the thermostat and see if it solves the problem, [not so unusual for a part to be DOA] it is a lot cheaper and easier to do then the water pump, if the new thermostat does not solve the problem and assuming you have done a proper coolant system bleed, [in fact if you have not bled the system, do so, an airlock can have the same results as a closed thermostat] replace the water pump, if it's close to time for a new timing belt, replace it at the same time as no more work is needed.94