How do you change the heater core in a 1991 Chevy S10?

Answer 1

Heater corePosition a drain pan under the radiator, open the drain valve and drain the cooling system to a level below the heater core. Disconnect the heater-to-engine coolant hoses from the core tubes on the firewall, in the engine compartment. From the passenger compartment (under the dash) remove the heater core rear case cover-to-cowl screws, then remove the cover from the vehicle. You will be lucky to get it out without taking off the whole dashboard that is what i had to do. Remove the straps or brackets from each end of the heater core. Carefully remove the heater core from the cowl and case.

Installation: Insert the heater core into the case, taking care not to damage the tubes as they are inserted through the cowl. Install the straps or brackets to the ends of the heater core and secure using the retaining screws. Install the heater core rear case cover and secure using the retaining screws. If moved for access, reposition and secure the dash mounted cabin light and housing. Connect the heater-to-engine coolant hoses to the core tubes. Connect the negative battery cable, then properly refill the engine cooling system. Run the engine at normal operating temperatures and check for leaks.