2000 Cavalier 2.0 Liter . Started loosing coolant. Pressure tesed no leaks. Found system pushing coolant out of overflow hose like a garden hose. Replaced thermostat, same problem. Fan runs @ 190 OK. I can only think there is a restricition in the system causing the backup. Before replacing hoses (upper and lower over $100 and special order wanted to see if anyone else has had this problem.