The International VT365 engine replaced the T444E in 2003. The VT365 was developed by International to better comply with more strict emissions requirements. The VT365 was many of the platforms the T444E was used including school buses and medium-duty trucks until 2016.
This VT365 diesel engine guide is a part of our Diesel Engine Guide series to help with buying a school bus for sale.
This article will dive further into the International VT365 engine including:
- Engine Overview
- Engine Specs
- Towing Capacity
- Life Expectancy
- Maintenance Requirements
- Typically paired transmissions
- Common engine problems
- Engine comparisons to the DT466, T444E, and the sister engine Ford 6.0L Power Stroke.
VT365 Engine Overview
Navistar International introduced its VT365 diesel engine family in 2003. It was a replacement for the Navistar International T444E, which was built in response to increased emissions standards in the U.S. during the mid-1990s. As emissions regulation increased, Navistar International responded to the market with the all-new 6.0L VT365 diesel engine and variants.
The VT engine, commonly known as the VT365, was used in Navistar International school buses, type A-2 bus chassis, and medium-duty trucks weighing up to 23,500 pounds in gross vehicle weight. Depending on the diesel engine’s use, it was known by other brand names, including the Ford Power Stroke and MaxxForce.
The VT365 diesel engine featured an electronic variable response turbocharger (EVRT) for enhanced low-speed acceleration. Digital electro-hydraulic generation two (G2) fuel injection technology helped the diesel engine comply with stricter regulations for lower emissions, especially for school buses.
The VT365 diesel engine variant, known as the 6.0L Power Stroke, was used in 2003 to 2007 model year Ford Super Duty trucks, and 2003 to 2012 model year Ford E-Series vans and chassis cabs. The 6.0L Power Stroke engine had the same basic structure as the VT365 but different components to reduce turbo lag and create better throttle response. It also was built with an upgraded Allison five-speed transmission.
In 2008, Navistar International rebranded its VT (and DT) diesel engines as the MaxxForce. The variant MaxxForce was a V8 diesel engine used in Ford Super Duty trucks with a series sequential turbocharger and a high-pressure common rail fuel injection system. Mechanics reported many issues with the injectors, head gaskets, water pumps and oil coolers in the variant Ford engines, especially when driven at higher power levels. Production on the MaxxForce ended in 2010.
Production of the Ford 6.0L Power Stroke engine ended in 2012, but production of the Navistar International V365 diesel engine continued until 2016.
Cat C7 Engine Specs
|Engine variations||Production Years||Horsepower||Torque|
2003 to 2016
175 hp @ 2600 RPM
460 lb-ft @ 1400 RPM
6.0L Power Stroke
(Ford trucks and vans)
2003 to 2012
350 hp @ 2600 RPM
570 lb-ft @ 2000 RPM
2008 to 2010
350 hp @ 3000 RPM
650 lb-ft @ 2000 RPM
Typical Paired Transmissions
The Navistar International VT365 diesel engine was paired with Allison 2000 and 3000 automatic transmissions. The Allison 3200 transmission was an option for Ford trucks, and it offered more power and control for rigorous driving conditions. An optional TorqShift 5-speed automatic transmission, featuring a tow-haul mode, also was available for Ford trucks.
VT365 Engine Towing Capacity
Depending on the specific model and application, the Navistar International VT365 diesel engine had peak power ranging from 175 to 230 hp and torque up to 460 lb-ft. at 1400 RPM. Ford Super Duty trucks offered the 6.0L Power Stroke and MaxxForce with higher peak torque for hauling.
VT365 Life Expectancy
The VT365 diesel engine was warranted for 150,000 miles, but mechanics report it could run for 350,000 in medium-duty trucks before requiring a major repair or rebuild. The engine also has a low-range dry weight of 1,062 pounds.
International VT365 Engine Maintenance Requirements
Extra care and high-quality fluids are needed for VT365 diesel engines, especially when operating under super-duty conditions (i.e., excessive idling, dusty environments, frequent hauling, and short trips without reaching full operating temperature). However, fuel economy can be up to 40 percent more efficient compared to a gas-powered truck engines.
Higher mileage engines will likely need component replacements in the aftermarket, such as pumps, sensors or transmissions.
VT365 Engine Oil Capacity: 19 quarts
|Engine variations||Normal conditions|
6.0L Power Stroke
|Engine oil & air filter: 10,000 miles/6 months|
(5,000 miles/3 months for the 6.0L Power Stroke version)
Fuel filter: 20,000 miles/6 months
Engine coolant: 300,000 miles/5 years (12,000 hours)
Transmission fluid & filter: 100,000 miles
VT365 Engine Problems
The VT365 diesel engine was produced to accommodate strict emissions regulations at the time. Mechanics comment most issues are still found in the variant 6.0L Power Stroke engine used in Ford trucks, which had high warranty repairs and buybacks.
- Exhaust gas recirculation (EGR) valve failures – Electronic EGR valves help control the flow of exhaust gas into the intake manifold. Mechanics report the EGR valve fails due to an electronic failure or carbon build up on the valve. Symptoms include black smoke, loss of power and a fluttering noise. To keep it running properly, mechanics recommend cleaning the EGR valve during every other oil change.
- Fuel injection control module (FICM) – FICM problems begin with low voltage in the vehicle’s electrical system, due to failing batteries or a low-output alternator. The FICM multiplies the voltage in the fuel injector circuit to fire the injectors, which may cause the engine to have a hard start or no start at all. Mechanics report this issue is more common in the Ford 6.0L Power Stroke engine.
Ford 6.0L Power Stroke Issues (Sister Engine)
The Ford 6.0L Power Stroke diesel engine had the same basic elements as the Navistar International VT365 engine. Mechanics report the 6.0L Power Stroke engine has many performance issues with its power-boosting and emissions reduction components. These issues include:
- EGR cooler problems – While EGR valve issues are noted for the Navistar International VT365, mechanics report they are more prominent in the 2003 model year 6.0L Power Stroke engines. The clean-emissions component is used to cool exhaust gas that is recirculated back into intake manifolds. Both EGR coolers and EGR valves prone to failure, due to soot buildup and clogs. Depending on the severity of the failure, the engine can hydro-lock and cause severe engine damage.
- Oil cooler faults – Mechanics report this is the most common issue with the 6.0L Power Stroke. The oil cooler lowers the engine oil temperature, and there are few warning signs for a clogged or restricted oil cooler. Silicone sand in the coolant system can cause restrictions and buildup. If the oil temperature gets too hot, it can cause gaskets and O-rings to fail. Mechanics should include these checks during regular maintenance schedules.
- Fuel injectors – The 6.0L Power Stroke engine uses split shot hydraulic electronic unit injectors to deliver fuel to the cylinders. Much like the FICM, the fuel injectors are very sensitive to poor fuel and oil quality. Fuel injector failures could be caused by dirty oil, low fuel pressure, mechanical failure or an electrical issue. Symptoms include hard starts, rough idle and black/gray smoke. Prevent failures by keeping oil clean and maintaining proper fuel.
- High pressure oil system (HPOS) – The 6.0L Power Stroke fuel injection system operates with very high oil pressure. The HPOS often experiences internal engine oil leaks due to deteriorated O-rings and high pressure. Symptoms often occur when the engine is hot, and they include hard starts, no starts and loss of power.
- Turbocharger problems – The 6.0L Power Stroke engine utilizes a single vane variable geometry turbocharger, which was designed to reduce turbo lag and create better throttle response. When the turbocharger fails, it has the same symptoms as a bad EGR valve. Carbon or rust can build up in the vanes of the turbocharger and cause an over-boost or no-boost condition. Instead of a replacement, the turbocharger sometimes can be taken out and cleaned.
- Cylinder head faults – A major problem with the 6.0L Power Stroke engine are the torque-to-yield head bolts, which in an over-boost condition could lead to blown head gaskets, and eventually a cracked cylinder head. A failed EGR system has been known to contribute to engines running hotter than expected. In turn, this may lower the yield point of the head bolts and in some cases even warp the cylinder head.
VT365 vs 6.0L Power Stroke
The Navistar International VT365 was used in International school buses, Type A-2 bus chassis and medium-duty trucks weighing up to 23,500 pounds in gross vehicle weight. The VT365 diesel engine is basically the same as its Ford-branded variant, known as the 6.0L Power Stroke. The 6.0L Power Stroke engine powered 2003 to 2007 model year Ford Super Duty trucks and 2003 to 2012 model year Ford E-Series vans and chassis cabs. The 6.0L Power Stroke was offered with transmission upgrades for more speed, power and torque.[Note: Navistar International had another diesel engine variant, called the MaxxForce, which were used in Ford Super Duty trucks. Mechanics reported many issues with the injectors, head gaskets, water pumps and oil coolers in the variant Ford engines that ran at higher power levels. Production on the MaxxForce ended in 2010, which was long before the production run ended for the basic VT365 and 6.0L Power Stroke.]
Mechanics report that the 6.0L Power Stroke came with many problems associated with various components, including fuel injectors, head gaskets and oil cooling systems. Ford warranties covered the diesel engine up to 150,000 miles, but mechanics report that the issues often appeared after that mileage point. Some mechanics think the Ford-version engine had more issues, because the exceeded power caused more stress than the basic design could tolerate.
While Ford stopped equipping its consumer trucks with the 6.0L Power Stroke engine in 2012, Navistar International continued to produce the VT365 for use in school buses and medium-duty industrial trucks until 2016.
|Feature comparison||VT365||Ford 6.0L Power Stroke|
|Production years||2003 to 2016||2003 to 2012|
|Horsepower||175 hp @ 2600 RPM||350 hp @ 2600 RPM|
|Torque||460 lb-ft @ 1400 RPM||570 lb-ft @ 2000 RPM|
VT365 vs T444E
Navistar International introduced the VT365 diesel engine in 2003 as a replacement for its retired T444E diesel engine. Both VT365 and T444E were used in Navistar International school buses. Additionally, they both had variant engines rebranded as the Power Stroke for Ford Super Duty diesel trucks and utility vans.
Navistar International created the T444E in response to increased emissions standards in the mid-1990s. To maintain power with cleaner emissions, the diesel engine came equipped with a Hydraulic Electronic Unit Injector system (HEUI). As emissions regulation increased, Navistar International discontinued the series and replaced it with the all-new 6.0L VT365 to better address emissions mandates.
While the T444E was designed for heavy-duty vehicles or severe-duty equipment, it was much lighter in weight (930 pounds) than the VT365 (1,062 pounds) and other competitor diesel engines. Like the VT365, the T444E has an absence of a wet-sleeve design, which makes it harder to repair and rebuild than other Navistar International diesel engines. The T444E had shorter production years than the VT365, which tends to make it more expense to repair with more scarcity of aftermarket components.
Navistar International reported that the VT365 provided better horsepower ratings, more acceleration and less noise than the T444E. The VT365 also has more components, such as the electronic variable response turbocharger (EVRT) to provide better towing power and reduced emissions per government mandates.
|Production years||2003 to 2016||1994 to 2004|
|Horsepower||175 hp @ 2600 RPM||Standard: 184 hp @2200 RPM|
Optional: 238 hp @ 2300 RPM
|Torque||460 lb-ft @ 1400 RPM||Standard: 460 lb-ft @ 1400 RPM|
Optional: 620 lb-ft @ 1400 RPM
VT365 vs DT466 / DT466E
The Navistar International DT466 / DT466E was designed for heavy-duty vehicles and severe-duty equipment, and it was introduced 1971 long before the VT365 diesel engine series launched in 2003.
Unlike the VT365 engine, the DT466 / DT466E series included a wet-sleeve cylinder design, which enhances engine durability and serviceability. The wet-sleeve design allows the engines to be rebuilt to factory specifications, sometimes without even removing the engine from the vehicle. Some mechanics claim the wet-sleeve design also gives DT466-equipped vehicles greater longevity, sometimes 700,000 miles before requiring a major repair or rebuild.
The MaxxForce VT brand had a short life within the production of the VT365 engines, but mechanics report that they were more problematic than the ones built under the DT466 series.
|Production years||VT365; 2003 to 2016|
MaxxForce VT: 2008 to 2010
|DT466: 1971 to 1994|
DT466E: 1995 to 2007
|Horsepower||VT365: 175 hp @ 2600 RPM|
MaxxForce VT: 350 hp @ 3000 RPM
|DT466: 250 hp @ 2400 RPM|
DT466E: 275 hp @ 24000 RPM
|Torque||VT365: 460 lb-ft @ 1400 RPM|
MaxxForce VT: 650 lb-ft @ 2000 RPM
|DT466: 660 lb-ft @ 1600 RPM|
DT466E: 800 lb-ft @ 1600 RPM