What is the recommended engine oil type for the vehicle?

The recommended engine oil type for the HMMWV is OE/HDO 15W-40 due to its specific formulation that meets the operational requirements of the vehicle. This oil type provides excellent protection and performance under a wide range of temperatures, which is essential for military operations where the vehicle may be exposed to extreme conditions in various environments. The 15W-40 oil offers a balanced viscosity that ensures proper lubrication during both startup and high-temperature operations, leading to reduced engine wear and improved longevity of the engine components.

Using this specific oil type aligns with the manufacturer’s guidelines, ensuring that the vehicle maintains optimal performance standards. In contrast, the other options do not provide the same level of protection or are not recommended for the HMMWV's engine specifications, making OE/HDO 15W-40 the superior choice for maintaining the vehicle's operational readiness.