Alright so my 95 Prelude 2.3 is overheating.

the funny part about it, is it used to take 2 - 3 hours of driving for it to do so. sometimes even up to 6 hours it would be fine.

it never truly overheats it only goes to the middle mark between optimum and the red.
i simply throw it in neutral and turn the heat on full and it goes back down and stays that way.
Any ideas?

 

if it's getting worse progressively.. ill bet that your coolant level is lower than before and that you have a very slow leak or you're due for a coolant flush..

 

I'm wondering if it has anything to do with the thermostat

 

check all of those things... cheap fixes.. but however, if your car overheats too much itll result in a blown headgasket.. which isn't a cheap fix.