Venting the cooling system (B36, B38, B46, B48) (Cooper)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2021 MINI Cooper, 2020 MINI Cooper, 2019 MINI Cooper, 2018 MINI Cooper, and 2017 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Risk of scalding!

Only perform this repair work after engine has cooled down.

IMPORTANT: You must protect the alternator against dirt contamination before carrying out any repair work on the cooling circuit.

Cover alternator with suitable materials - Failure to comply with this procedure may result in an alternator malfunction - Preliminary work needed:

Fill COOLING SYSTEM with vacuum filling unit.

Venting cooling system:

Evacuate cooling circuit and charge with vacuum.
Remove vacuum filling unit and top up coolant in expansion tank to 200 ml above maximum.
Close the lid on the coolant expansion tank.
Connect battery charger

Starting the cooling system bleeding procedure:

Switch the ignition on.
Set heater to maximum temperature and turn blower down to lowest speed.
FES (driving dynamics control) must not be set to ECO PRO!
Press accelerator pedal for 10 seconds to floor.
Then start the engine. The idle speed is automatically 1200 RPM.
After 3 min:
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 10 s.
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 10 s.
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 1 min
After 5 min, the thermostat is automatically supplied with current and the electric coolant pump is automatically switched on Protection in vehicle: Pay attention to dashboard temperature display.
After 6 min:
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 10 s.
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 10 s
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 2 min
After 9 min:
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 10 s.
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 10 s
- Press on accelerator for 10 s at about 3000 RPM.
- Idle for 1 min
11 min after starting the engine, charging/bleeding procedure is ended. The engine speed is again at nominal level. The thermostat current supply is cut and the electric coolant pump is switched off again.
Coolant bleeding procedure is ended.

IMPORTANT: Attention: The engine must be cooled down before the coolant level is checked.

Adjust the fill level in the coolant expansion tank to maximum.