The coolant should be replaced on a cold engine.
For more information on the cooling system, see Chapter Engine cooling, heating, ventilation and air conditioning systems.
1. Set the temperature control to the heater position at maximum temperature. Remove the radiator cap.
2. Jack up the front of the car and place it on supports. Remove the lower protective cover of the engine compartment and place a container under the radiator to collect the leaking coolant.
3. On m52 and M62 engines unscrew the plug of the hole for bleeding the cooling system and the plugs of the drain holes on the left and right sides of the cylinder block.
M62 Engine Cooling System Bleed Plug
M52 Engine Cooling System Bleed Plug
Plugs in the cylinder block of the M62 engine
4. Remove the drain plug at the bottom of the radiator and allow the fluid to drain completely.
5. Tighten the removed plugs to the required torque.
6. Fill the expansion tank with coolant in accordance with the Specifications.
7. Unscrew the cooling system bleeder plug and wait until the coolant with air bubbles stops coming out. Tighten the plug.
On diesel models, the cooling system is bled automatically through the upper pipe to a separate expansion tank.
8. Install the radiator cap and expansion tank.
9. Correct the coolant level and check the cooling system for leaks (see section Checking fluid levels, leak control).