2018 International LT — Coolant Capacity & Type

The 2018 International LT typically holds between 50 to 70 quarts (approximately 47 to 66 liters) of coolant, varying by engine and specific cooling system configuration.

Quick Answer

• Total Cooling System Capacity: 50-70 quarts (47-66 liters), depending on engine and configuration.
• OEM Coolant Spec: Predominantly uses an Organic Acid Technology (OAT) or Hybrid Organic Acid Technology (HOAT) coolant that meets Navistar MPAPS B-1 Type II or equivalent specifications. This is typically a red, pink, or purple long-life coolant.
• Mix Ratio: 50/50 prediluted or concentrate mixed with distilled water.

Capacity by Engine Option

The International LT series is known for offering various engine options, with cooling system capacities fluctuating accordingly. The most common engines for the 2018 LT include:

These figures are estimates. Always consult your vehicle's owner's manual or service information for precise capacities based on your specific VIN and build.

Flush Interval

Maintaining your coolant is crucial for the longevity of your engine. For the 2018 International LT:

• Normal Duty: Coolant flush and fill recommended every 600,000 miles, 12,000 hours, or 6 years, whichever comes first.
• Severe Duty (heavy hauling, extreme temperatures, dusty environments): Consider flushing every 300,000 miles, 6,000 hours, or 3 years, whichever comes first. Regular testing of coolant health using test strips is highly recommended to monitor additive levels.

How to Refill & Bleed

Properly refilling and bleeding the cooling system of a heavy-duty truck like the International LT is vital to prevent air pockets that can lead to overheating. Here's a general procedure:

1. Drain the System: With the engine cool, open the petcocks on the radiator and engine block (if equipped) to thoroughly drain the old coolant. Collect all coolant in an appropriate container for recycling.
2. Flush (Optional but Recommended): Close the drains and fill with distilled water. Run the engine with the heater on until it reaches operating temperature. Drain again. Repeat until the water runs clear. For best results, use a commercial flushing agent according to product instructions.
3. Refill: Close all drain points. Slowly add the correct type and mixture of new coolant through the fill neck. For large capacities like the LT, a dedicated coolant filling tool or a vacuum-fill system is highly recommended to prevent air entrapment.
4. Bleed the System:
   • Start the engine with the heater on full blast.
   • Allow the engine to warm up to operating temperature. The thermostat will open, allowing coolant to circulate through the entire system.
   • Monitor the coolant level in the surge tank/expansion tank; it will likely drop as trapped air escapes. Top off as needed.
   • Some International LT models, especially those with larger engines, may have a dedicated air bleed valve or hose located at a high point in the system (e.g., near the thermostat housing or on top of the radiator) that can be opened to assist in bleeding air. Consult your service manual for exact locations.
   • Squeeze radiator hoses to help dislodge air bubbles.
   • Take the vehicle for a test drive, then allow it to cool completely. Recheck the coolant level and top off if necessary. Repeat this process over the next few drive cycles.

Common Cooling System Issues for This Generation

The 2018 International LT, like many heavy-duty trucks, can experience specific cooling system challenges:

• EGR Cooler Failures: The Exhaust Gas Recirculation (EGR) cooler is a common failure point in modern diesel engines. Leaks can lead to coolant loss, white smoke from the exhaust, and even engine damage if left unaddressed.
• Radiator Leaks: Due to vibrations and environmental factors, radiators can develop leaks, particularly at end tank seams or from stone chips.
• Water Pump Issues: Failures can occur with the water pump bearing or seals, leading to leaks or inadequate coolant circulation. Symptoms include overheating or coolant puddles.
• Coolant Contamination: Mixing incompatible coolants can lead to gelling, silicate drop-out, and premature wear on cooling system components. Always use the specified coolant type.
• Sensor Malfunctions: Coolant temperature sensors or level sensors can fail, leading to incorrect readings, illuminated warning lights, or even engine derating.
• Hose and Clamp Degradation: Over time, hoses can become brittle or soft, and clamps can lose their tension, leading to leaks.

Regular inspections and adherence to maintenance schedules are key to preventing these issues.

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