If you have one hot and one cool heater core hose, it sounds like the heater core is plugged. The best thing to do is to remove the hoses and both flush and back flush the core to see if the water passes through it. At any parts store, you can get the flush. Just follow the directions that come with the cleaner.
Let me know if it helps.
Wednesday, December 9th, 2009 AT 9:29 PM