You may not need it as you dream about cruising through the Sahara desert, but when you open your eyes and realize you and your Discovery are driving through Michigan in January you'll be really pleased to have a working Land Rover heater core. Quite literally, the Land Rover heater core is the core of your interior heating system. Using water and coolant that's been heated by the engine, the Land Rover heater core acts as a heat exchanger, exposing as much of the hot water to the air from your climate control system as possible, thus heating it up. Your water pump circulates the coolant-in fact, the Land Rover heater core is always plumbed in to your engine's cooling system. However, there's a water valve under your hood that determines whether or not hot coolant circulates through the Land Rover heater core. When you turn up the heat on your dash, you're opening the water valve to let more hot water flow through. Much like your Land Rover's radiator (which it resembles), the Land Rover heater core is susceptible to leaks as it ages. This is particularly true if you haven't been rigorous about changing the coolant every other year. Since the Land Rover heater core is located inside the passenger compartment under the dash, a Land Rover heater core leak can't really be ignored the same way a radiator leak can be (though a radiator leak should be dealt with immediately too). If you let a Land Rover heater core leak go untreated, you not only risk overheating your engine from coolant loss, but you risk trashing your interior thanks to the coolant dripping onto your carpets, floorpans, and upholstery. We don't have exact numbers, but Land Rover engines and interiors didn't come cheap last time we looked. So if your truck is showing any of the symptoms of a bad Land Rover heater core, get it checked out and save money on your replacement Land Rover heater core here.