Heat issue

Hello, It is most likely that the coolant is still not full. Feel both heater hoses, see if they are hot. If not, check both radiator hoses to ensure they are hot. The heat will help you track where coolant is flowing. Also, the flanges where the radiator hoses connect to the radiator can break off inside the radiator hoses. This prevents flow of coolant. If the thermostat is not opening, the coolant will never make it to the heater core, and air in the system can cause the thermostat to stay closed for too long, especially when it is cold out.