1992 Dodge Caravan overheating

Other Category problem
1992 Dodge Caravan 6 cyl Wheel Drive Type unknown Automatic 90,000 miles

my car keeps overheating changed thermostat about 6 months ago, it stop the overheating, now during the winter I have the same problem, not heat and overheating, duringthe first time I replaced the thermostate and car keep overheating, I losen the radiator cap for about a week and that reduced the overheating, then I replaced thermostat and tightned radiator cap, problem stop, now I have same problem, do I need a new thermostat again or new radiator cap no visable leaks.