2025 Kenworth W900 Fluid Type Specifications

As an ASE-Certified Master Technician, I'm providing a comprehensive guide to all factory-spec fluids for the 2025 Kenworth W900. This timeless heavy-duty truck, renowned for its power and durability, relies on precise fluid maintenance to ensure its longevity and peak performance. Always consult your owner's manual or OEM service information for the most accurate and up-to-date specifications, as these can vary based on specific engine, transmission, and drivetrain configurations.

Quick Reference

Engine Oil

For the 2025 Kenworth W900, the engine oil specification is paramount and will depend on the specific engine installed. Kenworth W900s are commonly equipped with PACCAR MX-13 or Cummins X15 engines. Both typically require heavy-duty diesel engine oils meeting API CK-4 or API FA-4 standards.

• API CK-4: This specification offers improved oxidation stability, shear stability, and aeration control, making it suitable for a wide range of diesel engines, including those with exhaust gas recirculation (EGR) and diesel particulate filters (DPF).
• API FA-4: This is a lower viscosity oil primarily designed for newer GHG (Greenhouse Gas) 2017 compliant engines to improve fuel economy. It's crucial to verify if your specific engine is approved for FA-4 oil, as it may not be suitable for older engine designs or certain operating conditions.

Capacity: Engine oil capacity varies significantly. A PACCAR MX-13 engine typically holds around 40-45 quarts (10-11 gallons), while a Cummins X15 can hold around 36-44 quarts (9-11 gallons). Always check the engine dipstick and your owner's manual for exact figures.

Intervals: Oil change intervals for heavy-duty trucks can range from 20,000 to 75,000 miles or more, depending on the oil analysis results, duty cycle, and engine manufacturer recommendations. Many fleets utilize oil analysis programs to safely extend drain intervals and reduce operating costs.

Pitfalls: Never mix different engine oil types or grades unless specifically approved by the manufacturer. Using the wrong oil can lead to premature engine wear, reduced fuel economy, and potential damage to emission control systems.

Engine Coolant

The 2025 Kenworth W900 typically uses an Extended Life Coolant (ELC), which is an Organic Acid Technology (OAT) formulation. These coolants are usually red or purple in color and provide long-lasting corrosion protection without the need for Supplemental Coolant Additives (SCAs).

• PACCAR Spec 90001: This is the common specification for ELC in PACCAR engines.
• Cummins CES 14603 / CES 14408: These are common Cummins specifications for ELC.

Capacity: Coolant capacity can range from 12 to 16 gallons or more, depending on the specific cooling system configuration and radiator size.

Intervals: ELC coolants offer extended service life, often up to 600,000 miles, 12,000 hours, or 6 years, whichever comes first. Regular testing of the coolant