2019 International LT: Coolant Capacity and Type

The 2019 International LT holds between 12 and 15 gallons (45.4 to 56.8 liters) of coolant, depending on the engine and sleeper configuration.

Quick Answer

• Total Cooling System Capacity: 12 to 15 gallons (45.4 - 56.8 L)
• OEM Coolant Specification: Cummins CES 14603, Shell Rotella ELC Nitrite-Free (Red, OAT)
• Mix Ratio: 50/50 Pre-mixed or Concentrate mixed with distilled water

Capacity by Engine Option

The 2019 International LT was available with two engine options, the International A26 and the Cummins X15. While International does not list separate capacities, the total volume is influenced more by factors like sleeper cab configuration (which adds a rear heater core) than by the engine choice itself.

Flush Interval

For the 2019 International LT, the recommended coolant flush interval depends heavily on the type of coolant used and the operating conditions.

• Normal Duty: When using the factory-specified Shell Rotella ELC (Extended Life Coolant) or an equivalent OAT nitrite-free coolant meeting Cummins CES 14603, the initial service interval is up to 600,000 miles (965,000 km), 12,000 hours, or 6 years, whichever comes first.
• Severe Duty: In severe service applications (heavy hauling, frequent idling, extreme temperatures), it is recommended to test the coolant annually and adhere to a more conservative flush interval, potentially as low as 300,000 miles.

After the initial flush, subsequent intervals depend on the replacement coolant. If a similar ELC is used, the 600,000-mile interval can be maintained. If a different coolant chemistry is used, the interval must be adjusted to that coolant's specific lifespan, which may be significantly shorter.

How to Refill & Bleed

Properly refilling and bleeding the cooling system on an LT is critical to prevent air pockets, which can lead to overheating and engine damage. Due to the large volume and complexity, a vacuum filler is highly recommended.

1. Drain: Open the petcock on the lower radiator and drain the system completely.
2. Vacuum Fill (Recommended): The preferred method is to use a commercial cooling system vacuum filler (such as an Air-Lift tool). This tool pulls the entire system into a deep vacuum, removing all trapped air. You then use the vacuum to draw the new coolant mixture into the system, ensuring a complete, air-free fill.
3. Manual Fill (If necessary): If a vacuum filler is not available, fill the system slowly through the surge tank (coolant reservoir).
4. Bleeding: Unlike many passenger cars, there isn't a single simple bleed screw. The primary method is to run the engine with the heater set to full hot. Let the truck reach operating temperature (the thermostat must open) to circulate coolant and push remaining air to the surge tank.
5. Top Off: As the engine runs and air purges, the level in the surge tank will drop. Continue to top it off to the "MAX COLD" line as needed. Secure the pressure cap only after the system is stabilized and free of large air pockets.

Common Cooling System Issues

The International LT platform is robust, but like any heavy-duty truck, it can experience certain cooling system problems.

• EGR Cooler Failure: A common issue on many modern diesel engines. An internal leak in the EGR cooler can cause coolant to be consumed, leading to white smoke from the exhaust and unexplained coolant loss. It can also lead to overheating.
• Water Pump Leaks: The water pump is a wear item. Weeping from the pump's weep hole or a noticeable coolant drip from the front of the engine can indicate a failing seal or bearing.
• Hose and Clamp Leaks: With so many feet of hose and dozens of clamps, simple leaks at connection points are common. The plastic and rubber components can become brittle over time due to heat cycles. Regular inspection of all hoses, especially at the radiator, charge air cooler, and heater cores, is essential.
• Radiator Damage: As the front-most component, the radiator is susceptible to damage from road debris. Even minor fin damage can reduce cooling efficiency over time.

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