I had the radiator replaced a couple years ago and the heater was working fine after that. However, this past winter 08/09 the heater no longer gets warm anymore. It is not blowing the freezing cold air from outside, but, the air that comes out will not stay warm if I turn the heat up past the first notch. What can this be? I am hoping it might be just the hoses need replaced, but , am afraid the whole heater core might need replacement. Can anyone answer this for me if you expierenced the same problem. Thanks in advance.