The system must be filled with a mixture (also in the warm season) antifreeze and distilled water.
Attention: The system can be filled simply with clean water (especially in summer). But later you need to add an appropriate amount of antifreeze to it.
Coolant level in a cold engine (liquid temperature +20°C) must be between the FULL and LOW marks on the expansion tank.
Do not wait until the coolant level reaches the minimum mark. The liquid must be topped up in advance.
Cold fluid should only be added to a cold engine to avoid engine damage.
Attention: You can only open the cap on the expansion tank. Do not open the radiator cap when the engine is hot. When the engine is hot, open the cap on the expansion tank carefully. There is a risk of scalding with hot water! Cover the lid with a cloth. The cover should be opened when the coolant temperature is below +90°C.
Visually check the cooling system for leaks if the fluid level drops very quickly.