How can I tell if my heater core is working?
How can I tell if my heater core is working? These are normally the feed and return hoses for the heater core. With the engine warm and running, feel the hoses. If the heater core is working properly, both hoses should be warm or hot to the touch; one might be slightly cooler than the other, but not by much. What happens when a heater core is clogged? Coolant from the engine passes through this and a fan blows air across it. The warm air you feel from the HVAC vents is a result of this process. If there is...