Use the OBC hidden functions to pull up the engine temperature reading and then drive the car slowly and stay close to home. Normal temp is no higher than 95 C. Gauge is notorously useless. If overheating really takes place, you need to fully explore the thermostat, WP, radiator, etc. Best way to go on an aging car with no service history is to replace all the critical cooling system parts. Not expensive, especially if you DIY.