How to Change a Heater Core in Chevrolet Cars

by Contributing Writer; Updated June 12, 2017

The heater core in your Chevrolet car Chevy Chevrolet car is radiator-style unit, used to heat the interior cabin of your truck. Engine coolant flows, continuously, from the lower radiator hose to, and through, the heater core, causing the unit to heat. An attached fan forces heated air through the heater core fins and into the cabin when the heater is on. A faulty heater core leaks coolant onto the inside floorboard on the front passenger's side, signaling that a replacement is needed. Replacing the heater core can be a complicated, time-consuming repair, as it is hidden behind the passenger's side dashboard.

Under The Hood:

 How to Change a Heater Core in a 94 Chevy Truck

Turn off the truck and use a socket wrench to disconnect the negative battery cable.

Place a drain pan under the radiator and loosen the radiator drain plug with a socket wrench to drain the vehicle's cooling system.

Remove the glove compartment by removing its securing bolt on the inside with a socket wrench. Remove the lower knee bolster by removing its three securing screws with a Philips screwdriver and prying off the panel with a slotted screwdriver. Disconnect the three electrical connections underneath the panel.

Remove the center air distribution duct from the floor of the vehicle below the dashboard.

Use a slotted screwdriver to pry off the hinge pillar trim panels. Remove the blower motor cover and then remove the two screws securing the motor. Pull the motor out of the vehicle.

Remove the two screws from the rear of the steering wheel to remove the steering wheel cover. Remove the single bolt securing the steering wheel to the steering column with a socket wrench. Disconnect the electrical connections in the steering wheel and pull it off of the column.

Remove the coolant overflow tank by pulling it out of the engine compartment. Disconnect the heater hoses at the heater core's connections.

Remove the four attaching screws and the nut and then remove the heater case. Remove the seven screws and lift off the heater case cover. At this point, you can remove the bolts securing the heater core to the truck and pull the heater core out of the vehicle. Place the new heater core into the vehicle and reverse the removal process to install it. Do not forget to tighten the radiator drain plug and to add coolant to the radiator until it reaches the "Max" line. Reconnect the negative battery cable.

Items you will need

  • Socket wrench

  • Drain pan

  • Slotted screwdriver

  • Philips screwdriver

  • Replacement heater core

 How to Change the Heater Core in a Chevrolet S10

Remove the dashboard. The heater core in S10s is behind the main dashboard, and it must be removed to access the core. The front dash panel can be removed by unbolting several screws at the bottom of the panel, then pulling the panel away from the dash. Once this front panel is off, the primary dash can be unbolted from the firewall with four large bolts below the windshield. Several accessories may need to be taken out to unbolt the dash from the firewall, such as the radio or 4WD switches.

Drain the coolant from the core. There is a drain plug at the bottom right of the primary radiator that will empty the coolant system when unscrewed. Some residual coolant might remain in the core, but it will come out when the core is taken out later.

Uncouple the core from the coolant lines. These hoses are directly behind the oil filler tube and will come loose when squeezed with pliers. They are of different sizes, and it won't be necessary to mark them for later re-attachment.

Unbolt the core from its mounts behind the removed dash panel. Several bolts might be difficult to reach, but once free from the mounts, the core assembly slides up and out toward the interior of the truck. Lay a towel down when removing the core, as come coolant might splash out.

Insert the new heater core and bolt it into the mounts. The openings will fit into the holes provided in the firewall.

Reconnect the heater core hoses, and re-attach the dashboard and front panel.

Fill the coolant system with a 50/50 mix of antifreeze and water. Tighten the drain plug on the radiator, then fill it. Crank the truck up with the heater system on its maximum setting and continue to pour coolant into the radiator until it will not take in any more.

Items you will need

  • Socket set

  • Screwdrivers

  • Pliers or vice grips

 How to Change the Heater Core in a Chevy Blazer

Remove the front dash panel by turning the lower screws in a counter-clockwise direction, then unscrewing the single bolt on the lip of the instrument cluster and pulling the panel out. Remove the rear wiper switch and the 4x4 switches, if applicable. Lowering the tilt wheel will allow the panel to be totally removed.

Remove the radio, headlight switch module and glove box by turning their screws in a counter-clockwise direction.

Remove the main dashboard by unbolting it at the front, between the windshield and firewall. There are six to eight bolts holding it in, and, once they are removed, the dash can be pulled away from the firewall. Be careful not to pull too much, as the wiring harness could become damaged.

Drain the coolant system by turning the drain plug on the lower left corner of the radiator and allowing the fluid to fall into the drain pan. Uncapping the radiator can reduce the internal pressure.

Remove the heater core hoses, on the upper left of the engine bay, by pinching their hose clamps with a pair of pliers and pulling them off. Some models will have screw-type hose clamps; turning them counter-clockwise will loosen them. Age and heat may have stuck the hoses to the core nipples, and the hoses can be cut right at these nipples if necessary. Leave enough hose to reconnect the new core.

Unbolt the heater core's mounts with a socket wrench in a counter-clockwise direction. Once the bolts are free, the heater core can be maneuvered toward the windshield and slid out. Some coolant may splash out, so have a towel handy.

Replace the heater core with a new one by sliding it into place and securing the mounting bolts.

Reconnect the heater core's hoses, turn the radiator's drain plug clockwise to close it, then refill the coolant system with a 50/50 percent mix of coolant and water.

Reconnect the dashboard to the firewall, then replace the front dash panel and fasten its instrument cluster screw and bottom bolts.

Crank up the truck and add coolant until the heater core is filled and blowing hot air.

Replace the radiator cap.

Items you will need

  • Socket set

  • Screwdrivers

  • Coolant

  • Pliers

  • Vice grips

  • Drain pan

 How to Replace the Heater Core on a 1979 Chevy Truck

Let the engine cool. Open the hood of the '79 Chevy truck and locate the heater core tubes. They are on the passenger side of the firewall and stick out next to the blower motor box. Remove the hose clamps on the heater core with the flathead screwdriver, then pull the lines off of the heater core tubes.

Open up the passenger door and locate the climate control box under the dashboard. Disconnect the temperature door cable from the distributor duct adapter with your hands. Unbolt the metal fender liner from the fender with the 3/8-inch ratchet and socket. Pull the fender liner out of the fender well, revealing the heater core screws.

Unbolt the heater core case screws, working through the fender with the 3/8-inch ratchet and socket. Unbolt the heater core from the case with the 3/8-inch ratchet and socket and take it out of the case.

Install the replacement heater core into the case with the 3/8-inch ratchet and socket. Install the case back into the dashboard with the 3/8-inch ratchet and socket, then reconnect the temperature door cable.

Install the heater hoses onto the heater core on the firewall with the flathead screwdriver. Open the radiator cap and then fill the radiator with the 50-50 pre-diluted coolant. Turn on the engine, then turn the heater on to its highest position.

Look for any coolant leaks in the system. Let the truck get to normal temperature, then turn it off and let it cool down again. Open up the radiator cap again and fill with coolant if necessary.

Items you will need

  • Flathead screwdriver

  • 3/8-inch ratchet, extension and socket set

  • 50-50 pre-diluted coolant

  • Replacement heater core

 How to Replace the Heater Core on a 1992 Chevy S-10

Park the S-10 on a paved level surface. Set the parking brake. Allow the engine to cool down before working on it. Remove the negative battery cable with a ratchet and socket.

Remove the radiator cap. Make sure the engine is cool before you do this. Find the radiator drain plug at the lower passenger side of the radiator. Place a large drain pan under the drain plug. Unscrew the plug by hand, and drain the radiator into the drain pan.

Follow the heater hoses to the passenger side of the firewall. This is where the hoses hook to the heater core. Loosen the hose clamps with a flat screwdriver. Wrap some masking tape around the hoses and mark them so you can put them back on the right heater core fitting. Twist and pull off the hoses.

Remove the lower side panels from the dash by removing the two Phillips head screws.

Remove the two Phillips head screws from the instrument panel trim panel. The panel is mounted to the underside of the dash, directly above the instrument panel. It includes the right and left air vents and radio cover. Pull the panel straight back to disengage the clips that hold it to the dash. Remove the electrical connector from the back of the panel. Set the panel aside.

Use a ratchet and socket to remove the two small bolts that hold the radio to the dash. Slide out the radio and disconnect the electrical connector and antenna. Set the radio aside.

Use a ratchet and socket to remove the bolts from each end of the underside of the dash, then use ratchet and Torx bit to remove the two Torx screws at each end of the underside of the dash. Use a ratchet and socket to remove the four nuts that hold the steering column to the dash and firewall brace. Allow the steering column to hang down. Remove the center bolt from the underside of the dash.

Use a flat screwdriver to pry the speaker grills and defroster grills from the top of the dash and remove the small bolts that are now exposed. Pivot the entire dash downwards. Reach behind the dash and remove any other electrical connectors. Remove the bolt from the center of the main electrical connector on the driver's side of the dash and disconnect it. Remove the entire dash from the S-10.

Find the heater core cover on the passenger side of the S-10. There is a thick wire brace attached to the center of the cover. Use ratchet and socket to remove the bolt that attaches the brace to the center of the cover. Use the Phillips screwdriver to remove the six screws that hold on the cover. Remove the cover.

Use a ratchet and socket to remove the four mounting strap bolts that hold in the heater core. Remove the straps. There is a strap on the top and bottom of the core. Use the ratchet and socket to remove the small bolt from the clamp that holds the two metal tubes that run from the heater core out to the firewall. Pull the heater core straight back to remove it.

Reverse these steps to install the new core. Refill the engine with coolant, start the engine and check for leaks. If your coolant is still clean, you can reuse it.

Items you will need

  • Drain pan

  • Flat screwdriver

  • Masking tape

  • Marker

  • Philips screwdriver

  • Ratchet and wrench set

  • Torx bit set

 How to Replace the Heater Core in a Geo Metro

Unplug the negative cable from the Geo Metro's battery. Raise the car and drain the cooling system (into a clean container, if you plan to reuse it). Do this by opening the drain plug on the bottom of the radiator and then replacing it after all the coolant flows out.

Lower the car and remove the instrument panel (this should take at least two people). Disconnect the heater hoses where they connect to the heater core tubes at the firewall.

Detach the temperature and mode control cables from the heater housing. Take off the housing from the evaporator assembly, unless the car doesn't have air conditioning. In that case, remove the air duct from the housing to the blower motor assembly.

Disassemble the heater case assembly after removing it from the Geo Metro by undoing the bolts and nuts. Once you disconnect the heater case halves, you can remove the heater core from the case assembly.

Install the new heater core into the heater case assembly. Reassemble the case and put it back on the car. Reconnect the evaporator case assembly, mode control, temperature cables and heater hoses to the heater core.

Reinstall the instrument panel. Refill the cooling system (use fresh fluid, if there's any doubt to the old fluid's quality). Reconnect the negative battery cable.

Start the engine and let it reach normal operating temperatures. Check for leaks in the system and make sure the heater is operating properly.

Items you will need

  • Jack and jack stands

  • Clean container

  • Wrench

  • Screwdriver

  • Replacement heater core

  • Coolant

 How to Replace the Heater Core in a Geo Tracker

Remove the Core

Disable the Tracker's air bag system. Disconnect the negative battery cable, and then remove the Air Bag fuse, steering wheel side cap, connector positive assurance device and all inflator module connectors.

Drain the cooling system. Jack up the Tracker if necessary and place the SUV on jack stands. Crawl underneath and remove the drain plug on the bottom of the radiator, allow the coolant to flow into a container and then replace the drain plug.

Remove the instrument panel from the vehicle. This is a complex procedure, as described further in Section 2. It requires the help of an assistant and is the biggest reason you should seek expert advice.

Detach the right-side instrument panel center support and remove the evaporator (if the vehicle has air conditioning). Disconnect the SIR harness clip on the Sensing and Diagnostic Module bracket and the SDM electrical connector, and then remove the SDM bracket.

Disconnect the speedometer cable, antenna cable and floor duct from the heater case. Remove the electrical jumper harness to the air conditioning amplifier, the relay bracket and the heater assembly-to-chassis nuts from the engine compartment.

Take the heater case off the Tracker and remove the dampers and linkages from the case. Extract the heater core from the case by removing the core bracket screw and bracket.

Disassemble the Instrument Panel

Start removing the instrument panel by taking off the center console, lower steering column and glove box. Unplug the wiring harness connectors from the heater unit and blower motor assembly. Take off the connectors from the ignition switch, contact coil and combination switch.

Separate the steering column. Remove the column shaft joint bolt from under the hood and separate the steering column shaft from the lower steering shaft. Loosen all the brace bolts and (if equipped) the shift interlock cable from the ignition switch.

Undo the speedometer's cable and detach the instrument cluster and hood latch handle. Remove the radio heater control panel and heater control cables from the instrument panel. Disconnect and label all wiring harness connectors on the panel.

Loosen the panel's mounting screws and bolts. Remove the cover plates and mounting fasteners, starting with the side cover plates.

Make sure all cables, wires and hoses have been disconnected from the instrument panel. Then, have another person help you lift the panel out of the Geo Tracker.

Install a New Core

Install the new heater core into the heater case. Replace the core bracket and bracket screw, dampers and linkages to the case, and then put the case back in the Tracker.

Reconnect all the cables and connections from the heater case to the engine compartment. Proceed in reverse order, starting with the heater assembly-to-chassis nuts and bolts and finishing with the speedometer and antenna cables.

Reinsert the Sensing and Diagnostic Module, attaching all its connectors. Connect the evaporator, if you removed it, as well.

Replace the instrument panel on the Tracker. You'll need your assistant to help you position it, and then follow the reverse procedure to secure it on the vehicle.

Refill the cooling system, enable the air bag system and connect the negative battery cable. Run the engine until it reaches normal operating temperatures and then observe the climate control operation, checking for leaks in the system.

 How to Replace the Heater Core in a Chevy Impala

Removing the Old Core

Jack up the car and drain the Impala's cooling system. Loosen the water pump's drain bolt and let the coolant drain into a pan. Close the drain bolt and lower the car afterward.

Remove the heater outlet and inlet hose from the heater core (reposition the hose clamps to do so). Take off the right console extension panel, body control module and left side extension panel on the front floor console

Disconnect the left instrument center support bracket (pull away the carpet at its bottom to reach the nuts). Remove the accelerator control pedal from its position in the front of the dash.

Disengage the center floor ducts by raising the outlet duct while pushing the ducts down. Rotate the outlet duct forward in the car and pull down to remove it from the HVAC module.

Use a small chisel to remove all the heat stakes from the heater core cover. Loosen the nut behind the fuel line bracket. Remove the dash panel's stud at the heater hoses.

Pull the core's cover down enough to reach the HVAC module's locating pins. Slide the cover rearward until the drain tube clears the dash front. Remove the cover by sliding it down, rearward, and to the right. You can now remove the core.

Installing the New Core

Install the new core into the HVAC module, attaching a new seal onto the drain tube. Attach the core cover from the right side, sliding it up and forward into position.

Align the drain tube with the front dash hole and the core cover holes with the HVAC locating pins. Install the core cover screws, cutting and folding back the sound insulator near the center screw to ease that screw's installation.

Reinstall the dash panel stud at the heater hoses, tightening the nut behind the fuel line bracket. Align the center floor duct with the HVAC and push it up while rotating rearward to install it. Put the floor ducts and outlet duct back into the Chevy Impala.

Attach the accelerator control pedal. Pull the carpet back and position the left center support bracket, then tighten the bracket nuts.

Reconnect the left side front floor console extension panel and the body control module to the car.

Put on the outlet hose and inlet hoses to the core, securing them with their clamps. Refill the cooling system with the proper mixture of water and coolant.

Items you will need

  • Jack

  • Drain pan

  • Wrench

  • Small chisel

  • Replacement heater core

  • Water/engine coolant

 How to Replace the Heater Core in a Chevy Avalanche

Drain the engine coolant from your Cadillac Escalade into a clean container. Cover the container and set it aside for reuse. Then disconnect the negative battery cable and remove the air conditioning refrigerant. If you're not sure how to remove the refrigerant or don't have the proper equipment, do not attempt to improvise; have a more experienced friend help out.

Use the J 43181 quick connect tool to disconnect the inlet heater hose from the heater core; close the tool around the heater core pipe, firmly pull it into the quick connect end of the heater hose, then firmly grasp the heater hose and pull it forward to disconnect the inlet hose from the heater core. You will also need the J 43181 tool to disconnect the surge tank outlet hose from the heater core.

Remove or disconnect the accumulator, the instrument panel carrier, the HVAC module drain hose, all electrical harnesses and ground connections from the HVAC module, and the HVAC retaining nuts and bolts. Take the screws out of the heater core cover, remove the cover, remove the heater core cowl gasket from the heater core, and then pull the heater core itself out of the HVAC assembly.

Install the new heater core into the HVAC module. Inspect the heater core cowl gasket and replace it with a new one if necessary. Secure the HVAC module cover in place, then position the HVAC module and torque the mounting nuts to 90 inch pounds, the mounting bolts to 35 inch pounds.

Reconnect the HVAC module electrical connectors, then replace the instrument panel carrier, the accumulator, and attach the hoses to the heater core again. Make sure you hear an audible "click" when connecting the hoses; this is your guarantee that they are properly seated. Then reconnect the negative battery cable.

Refill the engine coolant system. Recharge the air conditioning refrigerant; if you don't have the proper equipment or knowledge to perform this step, get help from a mechanic or experienced friend.

Run the engine up to normal operating temperature. Check for proper climate control operation and verify that there are no coolant leaks.

Items you will need

  • J 43181 Quick Connect Connector Removal Tool

  • Wrench set

  • Screwdriver

  • Clean, dry container for coolant

 How to Replace a Heater Core in a 98 Chevy Pickup

Use the open-end wrench to disconnect the negative battery cable from the battery.

Open the radiator release valve on the bottom of the radiator and drain the coolant liquid into the pan.

Remove the mounting bolts from the modular duct using a socket wrench. These bolts can be reached from the inside of the glove box compartment, in the passenger side of the cabin.

Remove the modular duct from the glove box compartment.

Disconnect the heater hoses from the heater core. Plug the hoses when they are disconnected.

Remove the mounting bolts from the heater core with the socket wrench set. Remove the heater core next.

Install the new heater core in the place of the old one and reattach the bolts. Replace the modular duct and the hoses. Fill the radiator with a 50-50 water and coolant mixture.

Items you will need

  • Screwdrivers

  • Socket wrench set

  • Open-end wrench

  • Pan for radiator fluid

  • Towels to plug hoses

 How to Replace a Heater Core in a 1995 Chevy Lumina

Remove the negative battery cable and the plastic engine cover. Place a drain pan under the car, below the heater hose connections. Squeeze the tabs on the heater hose clamps with a pair of pliers and slide the clamps backwards onto the hoses. Twist the hoses to break them loose and pull them off the heater core nipples.

Remove the lower sound insulation panels under both sides of the dash using 7 mm and 8 mm sockets and a ratchet. Remove the lower center console, if equipped, and the lower air ducts from the bottom of the heater core cover.

Remove the eight 7 mm screws that attach the heater core cover to the evaporator case and slide the cover down and forward to remove it. The two screws along the back of the cover, between the cover and the firewall, are especially challenging to remove and will require the use of a universal joint and extension along with the 7 mm socket and ratchet.

Remove the screw that attaches the heater core bracket and slide the heater core out of the evaporator case. Rotate the inlet and outlet tubes on the new core to match the old core, and slip the new core into place, securing it with the bracket and screw.

Reinstall the heater core cover, air duct and console. Reinstall the lower sound insulator panels. Slip the heater hoses onto the inlet and outlet tubes and slide the hose clamps into place. Refill the engine with coolant to replace the coolant that was lost during heater core removal.

Items you will need

  • Socket set

  • Wrench set

  • Screwdriver set

  • New heater core

 How to Replace the Heater Core in a Chevy Silverado

Open the drain at the bottom of the radiator on your Chevy Silverado, and drain the coolant into a clean container that can be tightly covered and set aside for reuse. Then disconnect the negative battery cable and, if your Silverado has air bags, wait at least 2 minutes before performing further work to prevent accidental air bag deployment.

Disconnect the heater hoses from the heater core. Also disconnect the temperature control cable and the mode control cable from the heater case assembly. You'll also need to remove the instrument panel carrier, and be prepared to disconnect any electrical connectors that may get in your way. If you do disconnect electrical connectors, tag each end of the connector to ensure you don't get the wires mixed up later.

Remove the screws and nuts holding the heater case assembly in place, then remove the assembly and place it on a work bench. Remove the screws from the cover, open it, and extract the heater core, which looks a little bit like a waffle made out of graph paper with a couple tubes sticking out of it.

Return the heater core to the case and screw the cover into place. Return the heater case assembly to the vehicle and mount it in place, tightening the mounting screws to 35 inch pounds of torque and the nuts to 80 inch pounds.

Reconnect any electrical connectors you may have disconnected as well as the mode control cable and temperature control cable and the heater hoses. Replace the instrument panel carrier, then reconnect the negative battery cable.

Refill the engine cooling system and bleed air from it as necessary. Run your vehicle up to normal operating temperature and check for coolant leaks and normal climate control operation; remember that the heater may not actually produce heat until your vehicle is at normal operating temperature.

Items you will need

  • Wrench

  • Screwdriver

  • Clean, covered container

 How to Replace the Heater Core in a Chevy Camaro

Removing the Old Core

Make sure you remove the ignition key and disconnect the Chevy Camaro's negative battery cable. Jack up the car, place it on jack stands, drain the cooling system by removing the drain plug and letting the coolant flow into a container. Replace the drain plug and lower the car.

Disable the air bag system, if the Camaro has one. Remove the SIR fuse from the fuse panel and the left side sound insulator. Take out the connector positive assurance device and the SIR connector at the steering column's base.

Release the glove box by squeezing its sides to gain access to the heater core assembly. Disconnect the heater module cover (starting with the retaining screws), the clamp on the core's left side and the clamp for the tubes on the engine side.

Plug the hoses with rubber to keep them from leaking. Remove the core by pulling it toward the rear of the car.

Installing the New Core

Install the new core in place of the old one and connect the heater hoses to the core tubes. Reattach all the clamps and the core module cover.

Reconnect the SIR connector, connector positive assurance device, left side sound insulator and SIR fuse. Reattach the negative battery cable.

Refill the Camaro's cooling system with the correct mix of water and coolant/antifreeze. Turn on the car and the cooling system and check for any leaks.

 How to Replace a Heater Core in a 1997 Chevy S10 Pickup

Accessing the Core

Disconnect the truck's negative battery cable.

Open the drain plug at the radiator with pliers and drain the engine coolant into a large container. Move the container to the engine block drain plugs and remove those plugs to drain the remaining coolant.

Loosen the clamps for the heater hoses with pliers and disconnect the hoses at the engine side of the firewall. Plug the hoses with rubber plugs.

Unclip and unscrew the left and right lower panels on the dash. Pry off the instrument cluster bezel, and then unscrew and remove the radio, disconnecting the electrical and radio connectors. Pry out the defroster grille and the dashboard's speaker grilles with a trim stick.

Remove the bolts at each end under the dash for the pivot brackets, the Torx screws near the brackets, the nuts holding the steering column (lower the column afterward), the single bolt on the dash bottom near the center and the bolts behind the dashboard grilles.

Grab the dash and pivot it rearward to access and disconnect any electrical connectors. Lean the dash backward on its pivots so you can disconnect the main harness plug on the right side, then pull the dash out of the truck.

Unbolt and remove the pencil brace on the heater core cover using a wrench and then remove the screws on the cover with a screwdriver. Remove the cover.

Replacing the Core

Remove the screws that hold the heater core straps and the bracket over the heater core tubes. Pull the heater core out of the housing.

Install the replacement core in the housing, making sure it fits correctly within the heater core tubes. Bolt the brackets and straps in place and then close the heater core cover with its screws and pencil brace.

Reinstall the dash into the truck, connecting all electrical connectors and applying all bolts and screws.

Reconnect the defroster and speaker grilles, the radio and the instrument trim panels.

Connect the heater hoses to the firewall in the engine compartment.

Fill the radiator with engine coolant through the filler neck, using a fresh half-and-half mix of water and antifreeze if the old coolant is contaminated.

Reconnect the negative battery cable.

Items you will need

  • Wrench

  • Large container

  • Pliers

  • Rubber plugs

  • Trim stick

  • Screwdriver

  • Torx wrench

 How to Replace a Heater Core in a 1998 S10 Blazer

Heater Core Removal

Put on your safety glasses and rubber gloves. Raise the hood, and disconnect the battery cables, using the socket wrench. Place the recycling container underneath the radiator drain plug to capture the drained coolant.

Take off the radiator fill cap to relieve the pressure in the cooling system. Loosen the radiator drain plug, using a socket wrench, to drain out the radiator fluid, and re-tighten it. Leave the recycling container in place to capture the excess coolant sitting in the lower radiator hose.

Disconnect the lower radiator hose, where it attaches to the radiator. Drain the excess fluid into the recycling container.

Locate the heater core intake and return hose lines that protrude through the passenger's side firewall of the engine compartment. Detach the hoses from the core nipple by depressing the release clip with a flat-head screwdriver, while turning the hose, counterclockwise, and pulling it off, by hand.

Take out the Torx screws, located under the front dashboard lip, which hold the dashboard soft cover in place. Remove the underneath mounting bolts, which attach the dashboard frame to the interior firewall. This allows the entire dashboard assembly to swing free, providing access to the heater cover and core assembly downward from the windshield.

Remove the heater core intake and return hoses from the core nipple by releasing the squeeze clamps, using channel-lock pliers. Squeeze the clamp, and slide and twist the hose, as you pull them off.

Remove mounting bolts holding the heater core cover in place, using swivel sockets and extensions. Take out the mounting bolts attaching the heater core to the interior firewall. Disconnect the electrical wiring harness. Maneuver the old unit upward and outward, toward the windshield.

Heater Core Installation

Install the replacement heater core downward from the windshield. Mount the unit, using its bolts.

Reattach the return and intake hoses. The hoses are different sizes, so you can not incorrectly cross them. Reattach the heater core cover and bolt in place. Reconnect the electrical wiring harness. Reattach, mount and bolt in place the dashboard frame and soft cover.

Reconnect the intake and return hoses, located in the engine compartment, at the firewall. Snap the hoses into the core nipple. Connect the lower radiator hose to the radiator, and secure it, in place, using the squeeze-type hose clamp.

Fill the radiator with a 55/45 mixture of new antifreeze and distilled water. Reconnect the battery, and start the engine. Allow it to run for ten minutes to flush out trapped air within the cooling system.

Test the replacement heater core by turning the heater on and off, continually, while observing the change in temperature. Check for leaks at all hose connections and the passenger's side floorboard.

Items you will need

  • Rubber surgical gloves

  • Safety glasses

  • Torx screwdriver

  • One gallon of antifreeze

  • Socket wrench set

  • Swivel sockets and long extensions

  • Channel-lock pliers

  • Recycling container

About the Author

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