The heater core is similar to a radiator and is a part of the vehicles coolant system 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 . Is your heat not working or is your heater not hot you may have a clogged heater core so do a heater core flush and unclog it learn how to flush your heate. The easy way to replace your heater core in your ford explorer even recommended for ford dealerships pulling the steering wheel and dash board for one li. Heater core flush front rear cores ford expedition mountaineerexplorer and more check out my amazon auto accessories store lets make that weekend j