2000 Buick Century Low Coolant Sensor. I have a 2000 buick century with 105,000 miles on is with a black substance in the coolant reservior, and a dark. If you are looking at the engine from the front of the car it will be on the left side.
Low cooland warning light comes on after startup, usually goes out after driving 3 miles, but lately coming on after i have been driving ten or so miles. The light flashed low coolant all the time and it has plenty of coolant and its not running hot at all. I still got the low coolant light after installing the second new.