2025 International MV Coolant Capacity & Type

The 2025 International MV holds approximately 30-36 quarts (28.4-34.1 liters) of coolant, depending on configuration.

Quick Answer

• Total Cooling System Capacity: 30-36 quarts (28.4-34.1 liters)
• OEM Coolant Spec: Predominantly extended-life OAT (Organic Acid Technology) coolant, typically red or purple in color, meeting Navistar's proprietary coolant specification (e.g., CES 14643 or CES 14404 for Nitrite Free OAT). Always verify with your specific engine manual.
• Mix Ratio: 50/50 prediluted or 50% concentrate mixed with 50% distilled water.

Capacity by Engine Option

The International MV series typically features Cummins B6.7 or L9 engines. The coolant capacity can vary slightly based on the specific engine and chassis configuration, including radiator size and presence of auxiliary heaters.

Always consult your vehicle's owner's manual or service information for the most accurate capacity for your specific VIN.

Flush Interval

For the 2025 International MV, the coolant flush interval largely depends on the coolant type and operating conditions.

• Normal Duty: Typically, extended life OAT coolants can last for 600,000 miles, 12,000 hours, or 6 years, whichever comes first.
• Severe Duty: Vehicles operating under severe conditions (e.g., heavy-hauling, extreme temperatures, frequent idling) should consider earlier inspection and potential flushing, often around 300,000 miles, 6,000 hours, or 3 years.

Regular testing of the coolant's condition and freeze point using test strips or a refractometer is recommended to determine the actual need for a flush.

How to Refill & Bleed

Refilling and bleeding the cooling system on an International MV requires careful attention to ensure all air is removed, which is critical for proper cooling.

1. Safety First: Ensure the engine is cool before starting. Wear appropriate personal protective equipment.
2. Drain (if flushing): If performing a full flush, drain the system completely from the radiator and engine block drain plugs.
3. Refill: Close all drain plugs. Slowly add the correct type and mixture of coolant to the surge tank (or radiator, if applicable) until it reaches the 'COLD FILL' mark.
4. Start Engine & Bleed: Start the engine and run it at high idle with the heater on full blast (even if it's hot outside) to open the thermostat and circulate the coolant. Monitor the coolant level in the surge tank and top off as needed. Look for any visible air bubbles escaping.
5. Check for Bleed Screws/Valves: Some International MV models or specific engine configurations may have air bleed screws or valves on the thermostat housing, radiator, or heater lines. Open these briefly until a steady stream of coolant (without air bubbles) appears, then close them.
6. Vacuum Fill (Recommended): For best results and to prevent air pockets, a vacuum-fill tool is highly recommended for commercial vehicles like the International MV. This method evacuates all air from the system before refilling, ensuring a complete fill.
7. Monitor: After the engine has reached operating temperature and the thermostat has opened, drive the truck for a short period, then let it cool completely. Recheck the coolant level in the surge tank and top off if necessary. Repeat this check over the next few days.

Common Cooling System Issues

Owners of 2025 International MV trucks should be aware of common cooling system issues that can arise in commercial vehicles:

• Coolant Leaks: Due to the high mileage and demanding use, hoses, radiator seams, water pump seals, and EGR cooler systems (on diesel engines) are common leak points. Regularly inspect for drips or crusty coolant residue.
• EGR Cooler Failure: On diesel engines, the EGR (Exhaust Gas Recirculation) cooler is a known potential point of failure. A failed EGR cooler can lead to coolant loss, white smoke from the exhaust, and even engine damage if not addressed promptly.
• Radiator Clogging: Debris, scales, or improper coolant can lead to blockages within the radiator fins externally or within the core internally, reducing cooling efficiency.
• Thermostat Issues: A stuck-open thermostat can cause the engine to run too cool, impacting fuel economy, while a stuck-closed thermostat can lead to dangerous overheating.
• Water Pump Failure: The water pump is a wear item. Signs of failure include leaks from the weep hole, bearing noise, or overheating due to lack of circulation.
• Coolant Contamination: Mixing incompatible coolants can lead to gel formation, corrosion, and damage to the cooling system components.

Regular preventative maintenance, including coolant testing and visual inspections, is key to preventing these issues.

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