Here's why:
* Viscosity: The 15W-40 designation is a viscosity rating for engine oil. It indicates the oil's thickness at different temperatures. The "15W" means it's suitable for cold weather (winter), while the "40" means it's suitable for hot weather (summer).
* Specific Gravity: The 7.3L Powerstroke engine is a high-performance diesel that requires a robust oil with the correct viscosity and specific gravity to protect it under demanding conditions.
* Engine Wear: Using the correct oil helps to prevent engine wear and ensure optimal performance.
Important considerations:
* Oil quality: Always use a high-quality diesel engine oil that meets the specifications listed in your owner's manual. Look for oils that meet the following specifications:
* API CF-4: (older standard)
* API CI-4: (older standard)
* API CJ-4: (newer standard)
* Additives: Ensure the oil includes the right additives to protect your engine from wear, corrosion, and deposits.
* Synthetic vs. Conventional: You can choose between conventional and synthetic oil. Synthetic oil often offers better performance and longevity, but it's more expensive.
Note: While 15W-40 is the recommended oil for most 7.3L Powerstroke engines, always consult your owner's manual for the exact specifications and recommendations for your specific vehicle.
