The oil temperature sensor monitors the temperature of your motor oil. If your engine starts overheating without warning, there is a possibility that your oil temperature sensor is not working properly. If an oil temperature sensor is not working properly, your engine may overheat, or you may have an illuminated check engine light on your dashboard. Either issue requires expert diagnosis by a professional technician. Call Holland Car Care - San Mateo in San Mateo at 650-344-8815 if your car, truck, or SUV needs a diagnosis.