2015 Kenworth W900 Coolant Capacity & Type

The 2015 Kenworth W900 coolant capacity will vary depending on the engine and radiator size, typically ranging from 50 to 80 quarts (47 to 75 liters).

Quick Answer

• Total Cooling System Capacity: 50–80 Quarts (47–75 Liters)
• OEM Coolant Spec: Check engine manufacturer specifications—typically an OAT (Organic Acid Technology) or HOAT (Hybrid Organic Acid Technology) ELC (Extended Life Coolant) meeting standards like Cummins CES 14603 or Detroit Diesel DFS93K217.
• Color: Varies by manufacturer, but commonly red, pink, or purple for ELC coolants.
• Mix Ratio: 50/50 concentrate/distilled water pre-mix or concentrate.

Capacity by Engine Option

The Kenworth W900 in 2015 was available with several engine options, and the cooling system capacity is highly dependent on the engine and radiator configuration. Always consult your owner's manual or engine manufacturer's specifications for precise figures.

Flush Interval

For a 2015 Kenworth W900, using an Extended Life Coolant (ELC) as recommended by the engine manufacturer:

• Normal Duty: Up to 600,000 miles, 12,000 hours, or 6 years, whichever comes first.
• Severe Duty (heavy hauling, extreme temperatures, dusty environments): Consider reducing the interval by 25-50% or following your engine manufacturer's severe-duty recommendations, often involving coolant analysis at regular service intervals.

Always perform regular coolant testing (e.g., test strips for nitrites, silicates, and pH) to monitor the coolant's condition and determine if an earlier flush is necessary.

How to Refill & Bleed

Properly refilling and bleeding the cooling system of a Kenworth W900 is crucial to prevent air pockets that can cause overheating. Here's a general procedure:

1. Drain the System: With the engine cool, open the petcocks on the bottom of the radiator and engine block (if equipped). Allow all old coolant to drain completely.
2. Flush (Optional but Recommended): Close the drain valves. Fill the system with distilled water and a cooling system flush product if desired. Run the engine to operating temperature with the heater on high, then drain again. Repeat with distilled water until clear.
3. Refill: Close all drain valves. Begin filling the system slowly with the specified 50/50 ELC through the expansion tank or surge tank.
4. Bleed Air:
   • Start the engine and run it at a fast idle (around 1000-1200 RPM) with the heater on full blast.
   • Monitor the coolant level in the expansion tank and top off as needed. Some W900s may have a dedicated bleeder valve on the thermostat housing or upper radiator hose—open this slightly until a steady stream of coolant emerges, then close it.
   • Keep the radiator cap (if present and not a sealed system) off until the thermostat opens and coolant flows.
   • Once the engine reaches operating temperature and the fan cycles on, replace the cap/pressure cap. Squeeze the upper and lower radiator hoses repeatedly to help dislodge air bubbles.
   • Allow the engine to cool completely. Recheck the coolant level in the expansion tank and top off to the "cold fill" line.
5. Post-Procedure Check: Drive the truck and monitor the temperature gauge. Check for leaks and recheck the coolant level after the first few trips.

Note: Some modern heavy-duty trucks may benefit from a vacuum-fill tool, which evacuates air from the system before refilling, ensuring a complete fill without air pockets.

Common Cooling System Issues for this Generation

The 2015 Kenworth W900, while a robust platform, can experience cooling system issues common to heavy-duty trucks of its era, often exacerbated by high mileage and demanding operating conditions:

• Radiator Leaks: Over time, vibrations and road debris can cause leaks in radiator core tubes or tanks. Plastic end tanks are particularly susceptible to cracking.
• Water Pump Failure: The water pump