Why does the coolant have to be checked for sufficient frost protection before winter begins?

The coolant must be checked for sufficient frost protection before winter because of two main reasons:

1. Preventing Freeze: If the coolant freezes, it can expand and potentially crack the engine block or damage other components of the cooling system. This can lead to significant and costly repairs.

2. Protecting the Cooling System: Adequate frost protection ensures that the cooling system remains functional and does not suffer damage from freezing temperatures. If the system is compromised, it may lead to overheating or failure during operation, creating safety hazards.

In German traffic laws, maintaining a vehicle in safe working order, including the cooling system, is crucial for safety on public roads. Ensuring proper frost protection is a preventive measure that contributes to vehicle reliability and safety during winter conditions. Therefore, both reasons are necessary to fully understand why checking coolant before winter is important.