Q: How to remove and replace the evaporator core and A/C Expansion Valve in Ford Explorer Sport Trac?
A: For models through 2000, the removal of the evaporator core involves disconnecting refrigerant lines at the firewall, removing the coolant recovery tank, disconnecting Blower Motor wiring, and disconnecting the vacuum connector inside the vehicle. On the engine-compartment side of the firewall, three nuts are removed from the housing studs, allowing the blower motor/evaporator housing assembly to be pulled out of the vehicle. The two halves of the case are separated by removing 11 screws, and the evaporator core is taken out. Installation follows the reverse process, with the addition of 3 ounces of new refrigerant oil to the new accumulator/drier inlet tube and the possible replacement of the evaporator core orifice before reconnecting the lines. The system is then evacuated, recharged, and leak-tested. For 2001 and later models, the evaporator core replacement involves evacuating the system, recovering refrigerant, removing the suction accumulator, pinching off and disconnecting heater hoses, disconnecting electrical connectors, using a spring-lock-coupling tool to disconnect the evaporator tube-to-condenser refrigerant line, and rotating and leaning the housing forward for removal. Installation is the reverse process, utilizing new O-rings at the connections lubricated with 134A-compatible refrigerant oil.