Red Seal Truck and Transport Mechanic Practice Exam

What is one advantage of using synthetic oil in diesel engines?

1. Lower cost compared to conventional oil

2. Better performance and protection at high temperatures

3. Longer change intervals than conventional oil

4. Less environmental impact

The correct answer is: Better performance and protection at high temperatures

Using synthetic oil in diesel engines provides better performance and protection at high temperatures due to its superior thermal stability compared to conventional oils. Synthetic oils are engineered to maintain viscosity and resist breakdown under extreme heat, which is particularly important in highly stressed diesel engines that often operate at elevated temperatures. This characteristic allows synthetic oil to provide optimal lubrication and protection for engine components, reducing wear and extending engine life. In addition to its thermal advantages, synthetic oil also tends to have better flow characteristics at low temperatures, ensuring that the oil circulates quickly during cold starts. This feature can significantly reduce friction and engine wear when starting the engine in cold conditions, further enhancing performance and protection throughout the operating temperature range. While other options present valid points regarding synthetic oil, they do not capture the essence of why this specific advantage of high-temperature performance is crucial for diesel engines, which are often subjected to challenging operating environments.