Allow the cooling system to completely cool down. Using a thick cloth for protection, turn the radiator filler cap to the first stop. Step back and let the pressure release. Once the pressure has been released, completely drain the cooling system. Working within the engine compartment, loosen the clamps on the heater hoses at the engine compartment side of the firewall. Disconnect the heater hoses from the fittings at the firewall. Twist the hoses and carefully separate them from the heater core tubes. Plug or cap the heater core tubes to prevent coolant from spilling into the passenger compartment when the heater core is removed. Place a plastic sheet on the floor of the vehicle to prevent stains if the coolant spills. For 1993 and 1994 models, working in the passenger compartment, remove the four screws securing the heater core access cover to the plenum assembly. Carefully pull the heater core to the rear and down and remove it from the plenum assembly. For 1995 and later models, on 2011 models, remove the air conditioning 
Evaporator. Remove the instrument panel. On 2001 and later models, remove the PCM, the PCM heat sink and ground strap. Remove the heater plenum chamber. Remove the heater core cover, if equipped. Separate the heater core from the heater plenum chamber. Installation is the reverse of removal, with the following additions: Fill the cooling system. Run the engine, check for leaks and test the heater.