Your 1998 seems to run hotter in the winter now than in the summer just past--is that a computer control issue or do you have a problem that will show up later?

Engine temperature is controlled by the thermostat. An engine can often run hotter if the thermostat has started to fail or if the radiator is partially blocked. The computer is not involved in temperature control. Have the rad and cooling system flushed and change the thermostat at the same time. Have the heater core pressure tested and flushed out.