The coolant temperature sensor is an important tool for measuring the temperature of the engine improving performance and life time. Using this information’s the engine control module control different parameters achieving optimal engine control. Thermistor-based temperature sensors have been the choice for a variety of automotive applications enhancing the performance of car systems. In this paper an experimental stand was designed and realized in the laboratory to evaluate the accuracy of two thermistors NTC and PTC used to measure the engine coolant temperature. Based of the variation of the temperature characteristics curves function of resistance will be determined.