The heater core in your Chevrolet G20 van is the small device located in the dashboard that acts as a radiator and heats up the air before it is expelled by the blower fan. A faulty heater core means that no warm air will flow out of your heating system. Even worse, as the heater core continues to deteriorate, it can cause coolant to leak out or white smoke to pour into your vehicle. If this occurs, you should install a new heater core in your G20 as soon as possible.
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.
