A display on your liquid-cooled vehicle indicates that the temperature of your coolant is excessively high. What might be the cause of this?

The selected combination of causes for the excessively high coolant temperature is correct because all three options can independently lead to overheating in a liquid-cooled vehicle.

1. **Radiator Contamination**: A dirty radiator can obstruct airflow, diminishing its ability to cool the coolant effectively.
2. **Radiator Fan Failure**: If the radiator fan stops working, it cannot draw air through the radiator, which is essential for lowering the coolant temperature.
3. **Perforation in the Radiator System**: A leak in the radiator system can cause a loss of coolant, leading to insufficient coolant circulation and overheating.

In German traffic regulations, maintaining your vehicle's safety and mechanical integrity is critical. Overheating can lead to engine failure, posing risks to both the driver and other road users. Therefore, it's crucial to recognize all potential causes of a mechanical issue to ensure proper maintenance and safe operation of the vehicle.