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

by Chris MooreUpdated November 07, 2017

Items you will need

  • Wrench

  • Large container

  • Pliers

  • Rubber plugs

  • Trim stick

  • Screwdriver

  • Torx wrench

A bad heater core will make your Chevy S10 pickup's heating system impossible to work and you will need to replace it. As in many vehicles, the 1997 S10's heater core is stored within a housing mounted between the engine firewall and the dashboard. You will need to remove the dashboard in order to access the heater core. This may not be as complicated as it is with other vehicles, but it still requires precision and care.

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.

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