Bleeding Independent Heating (Thermo Top S)

Bleeding Independent Heating (Thermo Top S)

Top up coolant.
Remove front left wheel.
Remove trim panel from front left wheelhouse.







Fit special tool 17 0 002/005 to expansion tank and develop a pressure of approx. 1.5 bar. Check cooling system for water leaks while doing so.







Disconnect hose after bleed valve, ensuring that any air left in the independent heating unit is not forced past the bleed valve into the heater core. Open bleed screw (1) until bubble-free coolant emerges. Close bleed screw again and unfasten hose clip.







Additional work on M 73 engine:
Rotate screws through 90 °. Remove cover from cylinder head cover.







Additional work on M 73 engine:
Open bleed screw (1) until bubble-tree coolant emerges.

Start independent parking heater and wait for combustion. Start engine and run at 4000 rpm. The independent heating system assumes after-running mode. The circulation pump continues to operate. Within 2 minutes of starting engine, open and close bleed screw(s) on independent heating unit several times. Allow engine to warm up until thermostat valve opens. This completes the bleeding process. Turn off engine, allow to cool down and check coolant level; if necessary, draw off or top up.