The recovery of the air conditioning system refrigerant must be performed before the heater core can be removed. Have a MVAC certified tech recover the A/C system refrigerant.
- Disconnect the negative battery cable.
- Drain the engine coolant.
- Completely remove the instrument panel.
- From the engine compartment, label and remove all hoses and necessary wiring.
- Remove and plug all A/C lines.
- Remove and plug the coolant lines for the heater core.
- On Passat models using a heater core that is not completely surrounded by the air box housing, remove the self tapping screws if installed, then slide the heater core out of the housing.
- On A4 and Passat models with the heater core installed into the housing:
- Remove the heater box housing which contains the evaporator.
- Unclip the heater core box.
- Remove the heater core.
- Installation is the reverse of removal. Always make sure all seals are installed properly during the installation process.
- On Passat models using a heater core that is not completely surrounded by the air box housing, install the heater core with a self adhesive seal installed along the top of the fins on the side of the heater core that is near the inlet and outlet spigots and around the end of the heater core spigot housing to seal the heater core in the housing. If the heater core fit is slightly loose, secure it to the housing with self-tapping screws.
- If disassembled, seal all seams of the heater box with RTV.
- The balance of the installation is in reverse order of removal making sure to have a MVAC certified technician evacuate and recharge the A/C system.
Consult the under hood label for the correct refrigerant type and amount installed in the system. The R134A type of refrigerant was introduced as standard equipment in the 1993 models.