The oil level sensor on my '86 300E would began coming on after turning left for a few minutes, after time it would stay on longer, eventually it would come on and not go out until I stopped the car. During a recent oil change I removed the sensor and found the float was not moving freely. I cleaned it with kerosene until I could shake it and see/hear the float moving freely. I oiled it up and reinstalled it. It has worked perfectly since.