What type of engines use 15w40 oil?

15W-40 oil is commonly used in diesel engines, particularly in heavy-duty trucks, agricultural machinery, and construction equipment. It is designed to provide Excellent protection and performance in high-temperature and high-load conditions. Additionally, some gasoline engines, especially older models or those with higher mileage, may also benefit from using 15W-40 oil for better lubrication and wear protection.