Hello friends, I'm new here, I would like to ask

Hello, I would like to ask if someone could help me, because I have a problem with my Mercedes W210 of 96. It turns out that every time I stop the car empties the water through the deposit and heats up. Well I have taken it to the workshop and they have changed the thermostat but still doing it, someone could tell me what it can be or if it has happened to him. '? Greetings to all and thank you very much

Check radiator temperature when it is hot if it is lower than the plug radiator engine or water pump broken the water does not circulate liquid cylinder head tests that detects the cylinder head