What type of oil is used in a 1979 Hercules LDT 465 engine?

The 1979 Hercules LDT 465 engine typically requires a high-quality diesel engine oil, often specified as SAE 10W-30 or 15W-40. It's important to use oil that meets API (American Petroleum Institute) service classifications appropriate for diesel engines, such as CD or higher. Always refer to the owner's manual or manufacturer guidelines for the most accurate specifications.