83MercCapri

Well i've tried a few things and still can't seem to get heat. I went and got a flush, that didn't do it. I replaced the heater core. worked for the first night that didn't do it. Made sure the radiator and coolant system were full. that didn't do it. The temp gage is fluctuating day to day. one day it will be in the middle the next day the engine will stay cold. I have a new thermostat to put in but will that fix me heat? Its freaking cold out and all the help is greatly appreciated. Let me know if i need a new rad, or what.

I have a 1983 Mercury Capri
5.0 4bbl
114XXX miles

vfast

does your have a control valve?