coolant level sensor (on the expansion tank)
The coolant must be replaced when the cooling system is overhauled, in which the coolant is drained. In the event that the repair replaces the cylinder head, cylinder block, cylinder head gasket, radiator, heat exchanger or engine, the coolant must be replaced with a new one. During circulation, anti-corrosion additives are deposited on new light metal parts and thus form a durable anti-corrosion layer. The anti-corrosion additive in the used coolant is usually no longer sufficient to form a sufficient protective layer on new parts.
Fluid replacement procedures are described in Chapter Current service.
Warning! Drained coolant must not be reused. The coolant is poisonous and must not be disposed of with household waste.