Honda Repair: 91 Honda Civic DX Overheating issues, blown head gasket, coolant loss

Question
Hello,
I am having a frustrating time with my car.  It is a '91 Honda Civic DX, 1.5 litre, Automatic tran.  

At first it started to leak and overheat so I threw in some "stop leak" to fix it.  Worked for a few days and then it overheated again.  

Replaced the radiator, stopped leaking but it still overheated.  

Replaced the thermostat, didn't get hot right away  but the heater didn't work and then it would overheat.  

Replaced the waterpump, worked for a few days but the guage still reads hot.  It's not physically steaming or leaking but it will read way hot and then sometimes go back to regular temperature.  

things i should also mention are that a mechanic told me that the reservoir is leaking and to check the fan by turning on the a/c.  the fan checks out okay and the reservoir is full.  

also when i took it in for a tran rebuild the check engine light was not on, when they gave it back to me it was on.  

i'm hoping that the reason the guage still reads hot is because of a sensor problem?  i've been reading similar posts and i hope that it has nothing to do with the head gasket.  so should i have the engine checked out and hope for the best?  what possible sensors should be replaced?  

thank you.

Answer
Cheii:
The cooling system is a closed system, there should never be any coolant loss. Make sure radiator and reservoir are full, if there is a loss in coolant and the loss is not visible then you may have a bad head gasket. Check the cap on the reservoir to make sure it is not cracked or leaking anywhere, replace the cap if it is leaking anywhere. You have hit on the correct areas and about the only areas, thermostat, radiator and water pump. I would say one of the parts you replaced may be bad.
I would have the car diagnosed, if you do not have a blown head gasket driving your car in an over heated condition you will.
Hope this helps.
Bill