Filling the cooling system (Mercedes-Benz E-Class W123)

1. Replace the radiator and thermostat and connect all hoses.

2. Install and tighten the radiator and cylinder block drain plugs.

3. With the heater in the hot air position, fill the radiator or expansion tank with coolant. There are two level marks in the radiator filler neck: the lower one for a cold engine and the upper one for a hot engine.

4. Replace the filler cap and allow the engine to idle for a few minutes, then stop the engine and check the coolant level. Top up the coolant if necessary and replace the lid.

5. Bring the engine to normal operating temperature and recheck the level, remembering to relieve the pressure in the system before removing the cap.

(Original source of information: mercedesman.ru)