How to Replace the Heater Core in a Chevy Impalaby ContributorUpdated November 07, 2017
Items you will need
Replacement heater core
How to Replace the Heater Core in a Chevy Impala. Replacing your Chevy Impala's heater core is no easy task. There are several parts you must carefully remove or reposition to disconnect the core from the heating, ventilating and air conditioning (HVAC) module. This module and the core are located behind the car's floor ducts.
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.
Inspect the foam seal for the core on the lower HVAC case. Replace it with adhesive black foam tape if damaged.