Attention!
- Replace the coolant only on a cold engine, due to the possibility of getting burned by its vapors.
- Protect the generator from contamination.
- Place a container to collect the coolant at the drain point.
- Coolant should be added through the expansion tank of the cooling system and of brands strictly certified by the BMW company.
- The drained coolant must be disposed of.
- The mark on the expansion tank of the cooling system shows the maximum level of liquid in the system at a temperature of 20°C.
Draining the coolant must be carried out in the following order.
Prepare a container for draining the coolant and a clean rag. Unscrew the plug (valve cover) (1, Fig. 5.162) on the expansion tank of the cooling system.
Loosen the air bleed screw on the radiator expansion tank, if equipped, and remove the front engine accessory protection panel.
Remove the stiffening plate, unscrew the threaded drain plug at the bottom of the cooling system radiator and the plug (1, Fig. 5.163) drain hole on the cylinder block (on the right side). Drain the coolant and dispose of it.
Replace the cylinder block plug sealing gasket (M14x1.5) and tighten it to a torque of 25 N·m (2.5 kgf·m).
Replace the drain hole seal at the bottom of the radiator and tighten the drain plug to 8.0 N·m (0.8 kgf·m).
Turn on the ignition. Set the air conditioner control to the maximum temperature, the fan control to the lowest rotation speed. This opens the valves of the heater unit, and its additional pump starts working.
Remove the screw to bleed air from the engine cooling system. Cover the neck of the expansion tank with a clean rag.
Slowly pour coolant into the radiator through the expansion tank neck to the maximum mark. Wait until coolant without air bubbles starts to come out through the ventilation hole of the radiator expansion tank.
Tighten the plug (M8) of the ventilation hole on the radiator expansion tank to a torque of 8.0 N·m (0.8 kgf·m). Close the expansion tank of the cooling system. Remove the rag and send it for disposal.
Bleed the engine cooling system and check it for leaks. Start the engine, warm it up to operating temperature and check the tightness of the cooling system and the fluid level in the expansion tank of the cooling system. The technology for checking the tightness of the cooling system is similar to the "M54" engine.