How to Install a Heater Core in Vehicles

by Contributing Writer; Updated June 12, 2017

Vehicles heater core acts much like Vehicles radiator, in order to heat the inside of Vehicles. Prior to replacing Vehicles heater core, it is Vehicles good idea to verify that heating problems cannot be attributed to Vehicles leaky hose or an improperly connected clamp. If those components are intact, then move forward with replacing the heater core. Although the heater core itself is not difficult to replace, getting to the assembly on your Vehicles can be Vehicles challenge since it is located under the dashboard on the inside of the Vehicles.

Under The Hood:

 How to Install a Heater Core in a 1999 Grand Am

Drain the antifreeze from the coolant system into the drain pan by opening the valve on the bottom of the radiator with a wrench. If you keep the coolant clean, you can reuse it after completing the repair. Place wheel chocks behind the rear wheels. Lift the Grand Am with an automobile jack. Place a jack stand under the car and raise it to the frame.

Crawl under the Pontiac and locate the heater hoses on the back firewall. Remove the drain tube from the heater housing by loosening the clamp with a screwdriver. Disconnect the heater hoses by loosening the hose clamps with the screwdriver. Remove the jack stand from under the Grand Am and lower the vehicle to the ground with the jack.

Loosen the screws on the steering column cover with a screwdriver then remove it. Remove the sound insulators from each side of the car in the dashboard area. Disconnect the air duct from the unit with a screwdriver. Remove the screws from the rear floor outlet with the screwdriver.

Remove the heater core cover by loosening its screws with the screwdriver. Disconnect the heater core clamps from the housing with a wrench. Remove the heater core mounting bolts with the wrench. Pull the heater core into the passenger compartment.

Insert the new heater core in place under the dash console. Tighten the mounting bolts with the wrench. Connect the clamps that attach the heater core to the housing and tighten them with the wrench. Replace the heater core cover on the Grand Am and tighten the screws with the screwdriver.

Connect the rear floor outlet to the heater unit and tighten the screws with the screwdriver. Connect the air duct to the heater unit with the screwdriver. Install the sound insulators on each side. Attach the steering column cover and tighten the screws with the screwdriver.

Raise the Grand Am with the automobile jack. Place the jack stand under the vehicle and raise it to the frame. Crawl under the Pontiac and connect the heater hoses. Tighten the clamps with the screwdriver. Connect the drain tube to the heater housing and tighten the clamp with the screwdriver. Remove the jack stand from under the vehicle and lower the Grand Am to the ground with the jack.

Refill the radiator and reservoir with coolant. Start the vehicle and check for leaks around the hoses and inside the car.

Items you will need

  • Drain pan

  • Socket set

  • Wrench set

  • Automobile jack

  • Jack stand

  • Wheel chocks

 How to Install a Heater Core in an Audi A6 Quattro

Move the front seats as far backward as possible to allow for enough space to work.

Disconnect the negative and positive battery cables by loosening the clamps, and remove the battery.

Remove the cap on the coolant recovery tank to relieve the pressure from the system. Drain the coolant from the system by disconnecting the heater hoses from the tubes in the engine compartment, and applying compressed air to the upper tube. Catch the coolant as it comes out of the bottom tube. Remove the tube-to-chassis grommet on the heater core.

Remove the heater core storage compartment on the driver's side of the vehicle by loosening the bolts with a socket wrench, and the brackets from the heater core tubes from the passenger side of the vehicle.

Pull the heater core from the A/C-heater housing by tugging slightly. Pull the two coolant lines out of the heater core and remove the old heater core entirely.

Replace the old heater core with a new core, installing new clamps and O-rings at all connections. Insert the coolant lines back into the heater core during installation.

Replace the bolts and brackets from the heater core tubes on the passenger side of the vehicle. Replace the heater core storage compartment on the driver's side of the vehicle, and replace all bolts previously removed.

Reconnect the heater hoses at the heater core, tubes-to-chassis grommet, cap the to coolant recovery system and battery. Reconnect the positive and negative battery cables to the battery. Test the new system to ensure there are no leaks in the cooling system. Add coolant as needed to bring the level up to the proper amount.

Items you will need

  • Socket wrench

  • Screwdriver

  • Pliers

  • Compressed air

  • Container

  • Clamps

  • O-rings

  • Coolant

 How to Install a Heater Core in a Jeep Wrangler

Removal of Dashboard

Remove the negative battery terminal with an open-end wrench.

Remove the kick panel of the dashboard by removing the two screws holding it place with a Phillips screwdriver. This is the piece directly underneath the steering column. Set the panel aside.

Remove the two plastic dash pieces on the top and bottom of the steering column by removing the two screws holding the panels in place. Set these panels aside.

Remove all four electrical connectors inside the panel. Each connector has a release clip that must be depressed to release the connectors.

Remove the pinch bolt with a socket. This is located on the steering shaft next to the dash. These are 13 mm bolts. Remove the four nuts securing the steering column to the firewall using a 13 mm socket.

Allow the steering wheel to droop down. Grasp the wheel and pull it towards the rear of the vehicle. It will slide out. Set the steering wheel aside.

Release the wiring harness from underneath the dash by depressing the release lever.

Remove the driver's-side heat duct that connects to the blower motor by twisting and pulling simultaneously.

Open the glove-box door and remove the nylon strap. The screws needing to be removed are now accessible. Remove these screws with a Phillips screwdriver.

Remove the three Torx-head screws on each end of the dash. These are located behind the doors. Remove the four nuts on the upper dash pad by the windshield.

Remove the entire dash assembly by carefully lifting it out of the vehicle.

Remove HVAC unit

Disconnect the two heater hoses in the firewall with pliers. The top hose is larger than the other. Take note as to how the hoses are installed.

Remove the vacuum supply-line connector with a wrench. This is located underneath the heater hoses previously removed. Remove the evaporator drain tube with a wrench.

Remove the five HVAC housing nuts using a wrench. These nuts must be removed from the engine compartment.

Remove the HVAC assembly from inside the cabin of your Jeep.

Replace Heater Core Inside Housing

Remove all 7/16-inch screws holding the HVAC housing together. Gently remove the top section of the housing. You may need to pry the cover open, depending on the age of the vehicle.

The heater core runs from left to right inside the HVAC housing when viewing inside the vehicle. Replace the heater core with a new unit.

Install the two sections of the HVAC unit using a screwdriver.

Repeat all steps in the reverse order.

Items you will need

  • Ratchet and socket set

  • Torx-bit tips

  • Screwdriver

  • Pliers

 How to Install a Heater Core in a 1993 Chevy S-10

Removing the Old Heater Core

Disconnect the truck's negative battery cable.

Open the drain plug at the bottom of the radiator and drain the engine coolant into a large container.

Disconnect the heater hoses from the engine compartment side of the firewall by loosening the hoses' clamps with pliers.

Reach underneath the dashboard in the passenger compartment and remove the screws securing the heater core's rear cover to the cowl using a screwdriver. Remove the cover.

Loosen and remove the strap or bracket retainers for the heater core using the screwdriver, then remove the heater core from its cowl and case.

Installing the New Heater Core

Insert the heater core into the case and the core's tubes through the cowl, making sure you don't damage the tubes. Install the brackets or straps at the ends of the core and secure them with the retaining screws.

Connect the heater core's rear cover and secure its retaining screws with the screwdriver.

Connect the heater hoses to the core tubes through the firewall in the engine compartment then reconnect the negative battery cable.

Refill the engine coolant in the radiator, making sure you've closed the drain plug underneath. Use a fresh mixture of antifreeze and water if the old coolant is dirty.

Items you will need

  • Wrench

  • Large container

  • Pliers

  • Screwdriver

  • Antifreeze

 How to Install a Heater Core in a G20 Van

Open the van's hood and remove the negative cable from the battery with a socket wrench.

Put a drain pan under the van's radiator and use the socket wrench to loosen the drain plug. Let all of the coolant flow into the pan then tighten the drain plug.

Remove the heater hoses from the radiator and plug the core tubes with paper towels to prevent spillage.

Use the socket wrench to remove the two nuts from the distributor air ducts in the engine compartment.

Open the glove box and remove its two rear screws with a cross head screwdriver then remove it from the dashboard.

Remove the floor panel with a flat head screwdriver and unfasten the defroster duct-to-heater distributor screw located below where the glove box was located.

Use a Phillips head screwdriver to remove all of the side panel screws to gain access to the electrical connector. Disconnect the heater core's electrical connector.

Remove the heater core retaining straps then remove the heater core from the van.

Install the replacement heater core into the van, making sure that the case-to-core and case-to-dash panel seals are secure.

Reassemble the dash and reattach the hoses to the radiator. Remove the radiator cap and pour the coolant back into the radiator.

Reattach the radiator cap and reconnect the battery. Reattach the glove box.

Items you will need

  • Socket wrench

  • Drain pan

  • Paper towels

  • Cross head screwdriver

  • Flat head screwdriver

About the Author

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