2018 International MV Fluid Specifications & Capacities

The 2018 International MV is a premier medium-duty workhorse relied upon by fleets, municipalities, and independent operators across the country. As an ASE-certified master technician, I’ve serviced countless International MV trucks, and I can tell you that strict adherence to fluid specifications is the single most important factor in keeping these rigs on the road. The 2018 model year commonly features the legendary Cummins B6.7 or Cummins L9 engines, paired primarily with Allison automatic transmissions.

Because these trucks are highly customizable, fluid capacities will vary based on your exact wheelbase, engine, transmission, and axle configurations. Always verify your specific RPO codes and check your owner's manual or OEM service info for exact fill volumes.

Below is your comprehensive guide to the factory-spec fluids for the 2018 International MV.

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil (Cummins B6.7)	15W-40 Heavy Duty / API CK-4 (Cummins CES 20086)	15.0 - 17.5 qts (w/ filter)
Engine Oil (Cummins L9)	15W-40 Heavy Duty / API CK-4 (Cummins CES 20086)	23.7 qts (w/ filter)
Engine Coolant	Heavy Duty OAT (Nitrite-Free, usually Red/Extended Life)	25 - 35 qts (varies by core)
Transmission Fluid (Allison)	Allison Approved TES-295 or TES-668 (e.g., TranSynd)	15 - 19 qts (pan drop)
Transmission Fluid (Eaton)	Eaton PS-386 Synthetic Transmission Fluid	12 - 14 pints
Rear Differential (Single)	75W-90 or 80W-140 Synthetic API GL-5 (Dana/Meritor spec)	20 - 32 pints (varies by axle)
Brake Fluid (Hydraulic)	DOT 3 or DOT 4 (SAE J1703/J1704)	Fill to MAX line
Air Brake System	N/A (Keep air dryer cartridge serviced)	N/A
Power Steering Fluid	Dexron III ATF or Heavy Duty Hydraulic Fluid (Navistar spec)	3 - 4 qts
Diesel Exhaust Fluid (DEF)	API Certified DEF meeting ISO 22241	5 - 10 gallons
Windshield Washer Fluid	Standard all-season washer fluid	~1 gallon

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Engine Oil

Spec: 15W-40 API CK-4 (Cummins CES 20086) Alternative: 5W-40 API CK-4 (Synthetic) for extreme cold weather starting.

The lifeblood of your Cummins B6.7 or L9 is the engine oil. The 2018 International MV requires API CK-4 low-ash engine oil to protect the complex emissions systems, specifically the Diesel Particulate Filter (DPF). The OEM specification is Cummins CES 20086.

Intervals & Pitfalls: Standard oil change intervals range from 10,000 to 15,000 miles depending on duty cycle (severe vs. normal). Never use older API CJ-4 or CI-4 oils in this truck, as the higher ash content will rapidly clog the DPF, leading to thousands of dollars in emissions system repairs and forced regenerations.

Engine Coolant

Spec: Heavy Duty Organic Acid Technology (OAT), Nitrite-Free (Typically Red) Factory Fill: Fleetguard ES Compleat OAT or equivalent.

Medium-duty diesel engines generate a massive amount of heat, and the Cummins blocks in the MV rely on heavy-duty OAT coolant. This coolant is free of silicates and nitrites, utilizing organic acids to prevent cavitation and corrosion on the wet cylinder liners (on the L9).

Intervals & Pitfalls: OAT coolant is generally rated for 300,000 miles or 6,000 hours. Never mix OAT coolant with older HOAT (Hybrid OAT) or conventional green ethylene glycol. Mixing these can cause the additives to drop out of suspension, forming a highly abrasive gel that will wipe out the water pump seals and plug the EGR cooler.

Transmission Fluid

Spec (Allison Automatics): TES-295 or the newer TES-668 (e.g., Castrol TranSynd). Spec (Eaton Manuals/AMT): Eaton PS-386 Synthetic.

Most 2018 International MVs are equipped with Allison 2000 or 3000 series automatic transmissions. Allison mandates the use of fully synthetic TES-295 or the newer, backwards-compatible TES-668 fluids.

Intervals & Pitfalls: Using approved TES-295/668 fluid allows for extended drain intervals (up to 150,000 miles in general duty). Never use standard "universal" ATF, Dexron VI, or Mercon LV in these Allison heavy-duty transmissions. Using the wrong fluid degrades shift quality, destroys the clutch friction materials, and voids any remaining warranty. Always replace the spin-on Allison filter during a fluid service.

Rear Differential / Drive Axles

Spec: 75W-90 or 80W-140 Synthetic Gear Oil (API GL-5).

The International MV utilizes heavy-duty axles from Dana or Meritor. Factory fill is typically a full synthetic 75W-90 API GL-5 gear oil. If the truck operates in extreme heat or severe heavy towing conditions, an 80W-140 weight may be utilized per Dana/Meritor service guidelines.

Intervals & Pitfalls: Change the axle fluid every 100,000 to 250,000 miles depending on vocational use. Ensure the breather tube is clear of debris to prevent pressure buildup, which will blow out the pinion seal.

Brake Fluid (Hydraulic Brakes Only)

Spec: DOT 3 or DOT 4 (SAE J1703/J1704).

While many 2018 International MVs are ordered with air brakes (which require no hydraulic fluid, only regular air dryer desiccant cartridge replacements), some are equipped with hydraulic brakes. If yours has hydraulic brakes, they require standard DOT 3 or DOT 4 brake fluid.

Intervals & Pitfalls: Hydraulic brake fluid is highly hygroscopic (it absorbs moisture from the air). Flush the brake system every 2 years regardless of mileage. Moisture lowers the boiling point of the fluid, which can cause total brake fade during heavy braking on a downgrade. Never use silicone-based DOT 5 fluid.

Power Steering Fluid

Spec: Dexron III ATF or Navistar-approved Heavy Duty Steering Fluid.

The steering system on the MV operates under high pressures to turn those massive front steers. Depending on the exact steering gear (often TRW or Sheppard), the factory fill is generally a Dexron III equivalent ATF or a specialized clear hydraulic fluid.

Intervals & Pitfalls: Power steering fluid is often heavily neglected. Flush it every 50,000 miles. A whirring pump or stiff steering is often the first sign of fluid degradation. Check the reservoir dipstick and ensure you don't overfill, as the fluid expands significantly when hot.

Diesel Exhaust Fluid (DEF)

Spec: API Certified DEF meeting ISO 22241 standards.

To comply with strict EPA regulations, the Selective Catalytic Reduction (SCR) system requires high-purity Diesel Exhaust Fluid. It consists of 32.5% high-purity urea and 67.5% deionized water.

Intervals & Pitfalls: Fill as needed. The most common pitfall with DEF is contamination. Even a microscopic amount of dirt, diesel fuel, or tap water will permanently destroy the DEF header and dosing valve. Keep your DEF cap clean and only buy DEF that displays the API Certified / ISO 22241 seal.

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Proper preventative maintenance using exact factory specifications is what separates a million-mile truck from a constant headache. If you don't have the time or heavy-duty equipment to perform these fluid services yourself, don't risk your livelihood.

Find a trusted shop on Repairius.