Q: How do you replace the heater core on Ford Explorer Sport Trac?
A: To replace the heater core on 1994 and earlier models, remove the cable from the negative battery post and drain the cooling system. The clamps on the heater hoses should be loosened at the engine compartment side of the firewall so that they can be separated from the heater core tubes which are then capped. In the passenger compartment, unscrew, and pull out of plenum assembly, taking care not to damage them. For removing it, pull down and towards rear for taking out a heater core while finally installing it is just a reversal process making sure to replenish coolant and check for leaks.