What happens when a heater core is clogged?
What happens when a heater core is clogged? Hot coolant that has passed through other parts of the engine is run through the heater core as air is forced past it and into the cabin of the vehicle to heat it. A clogged heater core will prevent the coolant from passing through it, limiting the amount of heat that can be transferred. Why is my heater not working in my car? If your vehicle’s heater isn’t working as well as it used to, or has stopped working entirely, it may be the result of a clog in your heater core....