Q: How to remove and replace the heater core in Lincoln Town Car?
A: The following procedures involve the removal of several interior trim parts. In the case of 1981 and later Town Car models, the entire instrument panel must be removed or pulled back to access the heater assembly. To begin, disconnect the cable from the negative battery terminal and drain the cooling system, then disconnect the heater hoses from the heater core inlet and outlet tubes, and plug the heater core tubes to prevent coolant spillage. Remove the nuts holding the left end of the plenum to the firewall and the nut holding the upper left side corner of the evaporator case to the firewall. Disconnect the vacuum supply hoses from the vacuum source and push the grommet and vacuum supply hose into the passenger compartment. Proceed to remove various instrument panel trim components, steering column covers, cowl trim panels, defroster grille, and cross body brace to gain access to the heater core. Disconnect the wiring harness, vacuum hoses, and other components connected to the plenum assembly. Carefully move the plenum to allow clearance for the heater core tubes and the stud at the top of the plenum, and remove the plenum by rotating it from behind the instrument panel. To replace the heater core, follow the reverse procedure of removal. For 1982 through 1987 Continental and 1984 through 1992 Mark VII models, the process is similar. Additionally, if the vehicle has air conditioning, the refrigerant gas must be discharged, and the refrigerant lines going through the firewall need to be disconnected. For 1973 through 1979 Continental and Mark series, the heater core can be removed without discharging the air conditioning system. Drain the cooling system, disconnect the heater hoses from the heater core tubes, and remove the heater core cover to access the core. For 1970 through 1972 Continental and Mark series, disconnect the battery cable, drain the cooling system, and follow a detailed removal procedure to access and remove the heater core. Installation steps for each procedure should be carried out in reverse order.