REMOVAL & INSTALLATION
1983-88 524td, 528e, 533i, 535i, 633CSi, 635CSi, M5 and M6 Models
- Disconnect the battery ground. Remove the instrument panel trim at the bottom left. Remove the package tray.
- Have the air conditioning system discharged by a professional using an approved recovery/recycling machine.
- Remove the 2 bolts securing the trim panel underneath the evaporator unit.
- Remove the tape type insulation.
- Using a backup wrench, disconnect the low and high pressure A/C lines and cap the open ends.
- Unfasten the electrical connector for the evaporator. Disconnect the temperature sensor plug accessible from the outside of the evaporator housing.
- Remove the 2 bolts and then remove the bracket that braces the evaporator housing at the firewall. Remove the mounting bolt from either side of the housing.
- Unclip both fasteners and remove the housing.
- Now, move into the engine compartment and remove the rubber insulator from the cowl.
- Remove the mounting bolts for the cover which is located under the windshield.
- Remove the mounting nuts for the heater housing located on either side of the blower.
- Drain the cooling system, then disconnect the 2 hoses at the core.
- Working from inside the vehicle, remove the 3 electrical connectors for the heater housing. Pull off the 2 air ducts.
- Remove the 2 mounting nuts and remove the heater unit.
- Remove the air duct connections from the housing. Push the retaining bar back and then split and remove the 2 blower shells.
- Remove the retaining clips from the housing halves and split the housing. Then, remove the core.
Reverse the removal procedure, noting the following points:
- Cement a new rubber seal on to the core.
- Make sure that when reassembling the halves of the housing, all the distributor door flap shafts pass through the holes in the housing.
- Before reconnecting the refrigerant lines, coat the threads with clean refrigerant oil.
- Refill the cooling system with clean coolant and bleed it.
- Have the air conditioning system evacuated and recharged using an approved recovery/recycling machine.