The heater core is a smaller version of your car's radiator. It transfers heat from hot engine coolant into the cabin. But what should you do if your heater stops warming up the cabin?
Try a quick flush of fresh coolant. If that doesn’t do the trick, you could need a new heater core and related hoses, clamps, and tools.
Removing and replacing a heater core often requires removing components and part of the dashboard to access the heater box housing. The level of difficulty varies by vehicle year, make, and model. For example, removing and replacing the heater core on a 1954 Ford F-150 pickup might take an hour. But the same job on a 2004 F-150 could take 15 hours.
Replacing a heater core as a DIY project can save money.
Types of Heater Cores
Hot fluid flows into tubes, and a blower forces air through the fins.
Like your radiator, the heater core is a series of finned coolant tubes enclosed in tanks with fittings for the inlet and outlet hoses. Hot coolant flows into the tubes. The blower fan forces air through the fins. Heat flows through the vents into the cabin. Coolant returns to the engine.
Heater core flow configuration and materials evolved with automobiles. Brass and copper were widely used until the early 21st century. Aluminum is the most common material used today. (Modern composite aluminum and plastic tank heater cores are problematic and leak-prone.)
Automakers design heater cores for a tailored fit into the heater box. They are not generic or universal. Use the
eBay Parts Finder
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to find the best heater core and related parts for your ride. Enter your year, make, model, engine, and trim to search for heater cores designed for your vehicle. A new heater core may come with all the seals you need. However, we recommend searching for heater gaskets and seals to make sure there are no surprises mid-installation. New gaskets are inexpensive.
Buying a Used (or New Old Stock) Heater Core
You can save money with a used heater core. But beware of damage.
We recommend buying a new heater core. Damage from years of heat cycles and corrosion outweighs the benefits of buying a used heater core over a new replacement part.
This is a different story if you can find a used heater box in top condition. The heater core often shares its housing or heater box with a blower fan, air conditioning evaporator, sensors, foam seals, and model-specific HVAC components. A used or salvaged heater box assembly can be much less expensive than buying a new OEM replacement.
If a new old stock (NOS) or reproduction part for a vintage or classic car proves elusive, a used or salvaged heater core or heater box assembly might be the only option.
How much does a heater core cost?
For most vehicles, replacement heater core prices range from $20 to $100. Related parts such as heater control valves, core extension tubes, hoses, and clamps may be required. Always use new O-rings and seals for a leak-free installation. Confirm that your purchase includes new seals.
Vehicles with air-cooled engines use exhaust heat exchangers. Prices may vary if you drive older models, such as the Chevrolet Corvair, Citroen 2CV, Porsche 911, or Volkswagen Fastback. If the heat exchangers in your VW Bug oxidized into rust in 1976, eBay can help you find a rare factory-optional Eberspacher gasoline-fired heater for a toasty cabin.
The heater core depends on your car's engine cooling, heating, and ventilation system. Ensure the blower fan and blend door actuators work together to direct hot or cold air through the vents. Replace dirty or blocked cabin air filters to unchoke airflow and reduce odors.
Consider a radiator and cooling system flush before clogging up a new heater core with old rust. Buy a supply of new coolant. Discover everything you need to know about your
radiator
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and
hoses
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with our informative articles. Learn how to remove and replace cooling system components from the
water pump
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to the
thermostat
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with our step-by-step DIY videos.
Tools and Accessories for Heater Core Replacement
Did your heater stop warming up the cabin?
Removing a dashboard on the way to replacing a heater core can require an arsenal of tools. Be prepared with a wide world of fasteners, connectors, clips, and screwdrivers—including crosshead, hex, metric, Phillips, SAE, and Torx. See this list of required tools and supplies:
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New heater core
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New coolant
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Heater hose
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Fluid line clamps
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Sockets and ratchet
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Wrenches
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Quick-connect tool
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HVAC disinfectant spray
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Shop towels
You might not need everything on this list, but a mechanic's foam mat, kneeling pad, or old patio chair cushion can add comfort while contorting your body under the dash to reach that last Torx bolt holding the heater box to the blower fan housing.
Do you need special gear for frigid weather?
Getting coolant heat from the engine to the cabin may require specialized equipment in extremely cold operating conditions. Button up your radiator with a winter front grill cover for faster engine warm-ups and quicker interior heating. Consider a plug-in engine block heater to keep the oil and coolant warm overnight. That will enable easier starts on arctic mornings.
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This article is meant to provide general guidance only. Automotive maintenance, repair, upgrade, and installation may depend on vehicle-specifics such as make and model. Always consult your owner's manual, repair guide for specific information for your particular vehicle and consider a licensed auto-care professional's help as well, particularly for advance repairs.
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