Warning: Do not attempt to remove the expansion tank cap while the engine is hot - you risk scalding. Do not leave the coolant container open for a long time, as it is poisonous.
Prevention
- A closed cooling system does not require regular topping up of the fluid. If you have to do this often, there are leaks in the system. Check the radiator, all hoses and connections for signs of leaks. If a leak is found, fix it as soon as possible.
- Use antifreeze all year round, not just in winter. Do not top up the cooling system with clean water, as antifreeze will lower the boiling point and raise the freezing point.
1. The coolant level depends on the engine temperature. When the engine is cold, the coolant level should be between the "MAX" and "MIN" marks on the side of the tank wall. When the engine is hot, the coolant level may be slightly above the "MAX" mark.
2. If it is necessary to add coolant, wait until the engine has cooled down. Loosen the expansion tank cap slightly to relieve pressure in the system, then loosen and remove it.
3. Add a mixture of antifreeze and water through the filler neck of the expansion tank to the "MAX" mark. Install the cap and tighten it securely.
Original source of information: www.mercedesman.ru