W123 300D overheating

[Schmohey]

My 85 300D has heated up to 120C and the coolant started to overflowed out of the reservior. I bought a thermostat during the winter for replacement, since the temperature took forever to get to 80C. Now that I replaced the thermostat, I filled the coolant reservior with water (for a flush). Started the car, the temperature gauge reached 80C very quickly, and still climbs up. It went up to 110C and still started to climb up. I turned off the car, and drained the water out of the radiator. The water was not hot, and it was like the same water(cold) that I put into the reservior. There are no water passing through the upper radiator hose. It seems like there's no water going to the engine to cool it down. Any suggestions?