What are the requirements of lubricating oils for diesel engines?

The selected combination of requirements for lubricating oils in diesel engines is accurate because each option addresses a crucial function of engine oil in maintaining engine performance and longevity.

1. Reducing wear is essential because proper lubrication minimizes friction between moving parts, preventing damage and extending the engine's lifespan.
2. Heat resistance is vital as diesel engines operate at high temperatures. Oils must withstand these conditions without breaking down to ensure consistent lubrication.
3. Being fluid during cold periods ensures that the engine oil can circulate effectively upon startup, reducing wear during initial operation when parts may not be adequately lubricated.

In German traffic regulations, ensuring proper vehicle maintenance, including the use of suitable lubricating oil, is crucial for safety and environmental concerns. Adhering to these requirements helps keep vehicles in optimal working condition, reducing the risk of breakdowns or accidents on the road.