2020 Kenworth W900 Coolant Capacity & Type

The 2020 Kenworth W900 typically holds between 60 to 75 quarts (approximately 57 to 71 liters) of coolant in its cooling system, depending on the specific engine and cooling system configuration.

Quick Answer

• Total Cooling System Capacity: 60-75 quarts (approx. 57-71 liters)
• OEM Coolant Specification: Extended Life Coolant (ELC) – Red/Pink, OAT/NOAT (Organic Acid Technology/Nitrited Organic Acid Technology). Specifically PACCAR MX Engine Coolant or a compatible heavy-duty ELC meeting CAT EC-1, ASTM D6210, and TMC RP-329/330 standards.
• Mix Ratio: 50/50 Pre-Diluted or 50% Coolant Concentrate with 50% Distilled Water.

Capacity by Engine Option

The Kenworth W900 for 2020 was available with several engine options, primarily the PACCAR MX-13 and Cummins X15. The cooling system capacity can vary slightly between these larger displacement engines and radiator options.

Flush Interval

Maintaining the correct coolant and adhering to flush intervals is critical for heavy-duty truck longevity.

• Normal Duty: Typically 300,000 to 600,000 miles, or 3 to 6 years, whichever comes first, for Extended Life Coolants (ELCs) with proper coolant filter maintenance and SCA (Supplemental Coolant Additive) testing if applicable for your ELC type.
• Severe Duty: For vehicles operating under heavy loads, extreme temperatures, or frequent idling, a more frequent inspection and flush interval is recommended, potentially at the lower end of the "Normal Duty" range.

Always refer to your Kenworth W900 owner's manual or the specific engine manufacturer's guidelines for the most accurate and up-to-date maintenance schedule.

How to Refill & Bleed

Properly refilling and bleeding the cooling system on a Kenworth W900, especially with its large capacity, is crucial to prevent air pockets that can lead to overheating.

1. Drain the System: With the engine cool, open the petcocks on the bottom of the radiator and engine block (if present) to fully drain the old coolant. Flush with distilled water until clear.
2. Close Drains: Securely close all drain points.
3. Refill Slowly: Begin filling the system through the radiator fill neck or the surge tank (expansion tank) using the specified 50/50 ELC. Fill slowly to allow air to escape.
4. Idle and Monitor: Start the engine and let it idle with the heater on high. Keep the radiator cap (or surge tank cap) off and observe the coolant level. Top off as needed.
5. Burp Air: Squeeze the upper and lower radiator hoses repeatedly to help dislodge air bubbles. Some W900 models or engines may have dedicated air bleed valves; open these until a steady stream of coolant emerges, then close them.
6. Drive Cycle & Recheck: Once the thermostat opens and the system is at operating temperature, take the truck for a short drive. Allow the engine to cool completely, then recheck the coolant level in the surge tank and top off to the "COLD" fill line. This may need to be repeated over a few drive cycles.
7. Vacuum Fill (Recommended): For best results and to eliminate air pockets efficiently, a vacuum-filling tool designed for heavy-duty systems is highly recommended. This evacuates all air from the system before refilling, ensuring a complete fill.

Common Cooling System Issues for this Generation

The Kenworth W900, while a robust platform, can experience cooling system issues common to heavy-duty trucks, particularly concerning its large engines and demanding applications.

• Radiator Leaks: Due to vibrations, age, or road debris, radiator fins and tanks can develop leaks. Overheating and constant coolant loss are symptoms.
• Hose Failures: Large diameter hoses can degrade, crack, or soften over time, leading to leaks or collapses under vacuum.
• Water Pump Failure: The water pump is a critical component; signs of failure include leaks from the weep hole, bearing noise, or overheating.
• Thermostat Malfunctions: A stuck-open thermostat can lead to the engine running too cool, reducing efficiency, while a stuck-closed one causes rapid overheating.
• Coolant Filter Issues: Heavy-duty trucks often use coolant filters, especially with conventional coolants. Clogged or improperly maintained filters can restrict flow or fail to deliver SCAs, leading to cavitation erosion.
• EGR Cooler Leaks: With modern emissions systems, EGR (Exhaust Gas Recirculation) coolers are a common point of failure, leading to coolant loss, white smoke from the exhaust, and potential engine damage if coolant enters the combustion chamber.
• Air Entrainment: Due to the large system volume, incomplete bleeding can leave air pockets, causing localized hot spots and overheating. This is why proper bleeding or vacuum filling is essential.

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