ok I have a problem
I just bought this 90 Spirit 2.5 non turbo and had a problem with no heat. so I replaced the thermostat. then the temp gage started to swing hi and then come down to around 1/4 still poor heat the car ran fine for over a week.
today I was driving the car to work and the gauge said it was over heating so I drove it home the "check gauges" light came on then the
temp dropped back down to 1/4 and stayed there I still went home
I didnt drive that far from the house before returning

tonight I took the car to the store .. about 2 miles same thing the gauge said it was overheating this time I checked the top radiator hose and it was cold so I sat for a bit for it too cool down and started home NOW I had some heat but it was short lived . I had to pull over and let it cool down then came home and here I am

coolant seemd ok it was pressurized I havent checked the level yet but there was some in the reserve
It needed 1 qt of oil so I added some at the store
Also I get a bad squel from the belts and My lights dim Im thinking I need to check the alt. belt

ok thats it can anyone help me out

Well, the serpentine belt on the alternator drives your water pump. I would tighten that or replace it ASAP. Also I would pick up a new coolant temp sensor. If that does not fix your problem it could be your heater core which you can find on eBay cheap.

thanks Ill try that

coolant temp sensor i had same problem, i changed 3 thermostats 2 raid caps, a waterpump, raidiator, all for the sensor, good luck with it