My needle after being on for 10mins or so is about 3/4ths up, sometimes half way, driving around it always stays at about half - 3/4ths.

The fan is always on... I live where its always pretty cold...

My dad used to own the car, I don't ever recalling him changing the coolent, nor does he.

How exactly do I go about changing the coolent? I'm pretty sure its really gunked up.

Also should I clean the water pump, I read they can become gunked up and not function as well.

 

Take a look at the fsm. THere's a link to download it in the sticky.

 

Will the engine take damage from running with the needle halfway up? ( whatever temp that is?)

Im currently driving my car this way and its leaking coolant into the engine, i got a spare engine ready too go in so im not verry fuzzed, but i dont NEED too destroy the old one just because of that, was hoping i could postpone the switch if i just made sure too fill up the coolant at all times when getting low..

 

Halfway is no problem.

Sounds like either a stuck thermostat, clogged rad or bad pump.

Cooling system troubleshooting:
http://www.aaroncake.net/rx-7/cooling.htm