Ford 3.2L Power Stroke I-5

The 3.2L Power Stroke diesel is an adaptation of the 3.2L Duratorq (also 3.2 TDCI) found in Ford's global powertrain portfolio. After adopting more stringent emissions controls, the engine was brought to the United States market for the 2015 Ford Transit van. Much speculation was sparked that the Transit may have simply been a test pilot to gauge the popularity of the engine platform as a possible future option for the company's flagship Ford F-150. However, these theories were proved false when Ford introduced the [short-lived] 3.0L Power stroke to the F-150 engine lineup for the 2018 model year.

3.2L Power Stroke engines belong to the "Puma" engine family; a series of inline 4 and 5 cylinder diesel engines ranging between 2.0 and 3.2 liters in displacement. While the I-5 Power Stroke didn't land in the states until 2015, the first Puma engine was introduced globally in 2000.

3.2 Power Stroke Design Features

Engine Block

The 3.2L Power Stroke is an inline 5 cylinder, 4 stroke diesel engine with dual overhead camshafts. The engine block is produced from gray cast iron and features a weight saving aluminum cylinder head. While the I-5 arrangement isn't particularly common, it shares some advantages of an I-6 without the packaging restraints and while avoiding some of the operational limitations of an I-4. This engine has a relatively undersquare bore-stroke ratio of 0.89; the long stroke is a major contributing factor to the engine's broad torque curve, which maintains at least 90% of its peak torque rating (350 lb-ft) through 2,750 rpm.

Cooling & Lubrication Systems

A traditional cooling system with a belt driven mechanical water pump is found on the 3.2L Power Stroke. The engine cooling fan is mechanically driven by the engine, but is electronically controlled via a pulse width modulated signal provided by the PCM. The coolant capacity is relatively low at 3.5 to 3.9 gallons, depending on the whether the vehicle is equipped with an optional auxiliary heating unit.

An externally mounted oil cooler is built into the lube oil filter adapter. Although the coolant capacity is seemingly small, the lube oil capacity, at 12 quarts, is quite large for the engine's small displacement. By contrast, the F-150's 3.0L Power Stroke V-6 has a 6.5 quart engine oil capacity. It is likely that oil plays a critical role in engine cooling for the 3.2L Power Stroke.

A variable displacement oil pump is utilized to provide lubrication through the engine. The oil pump provides approximately 15 psi of oil pressure at idle and 44 psi at engine speeds of 2,000 rpm and above.

Fuel System

The heart of the 3.2L Power Stroke fuel system is a high pressure common rail injection system fueled by a Siemens VDO K10 injection pump that is chain driven off of the engine crankshaft. The high pressure fuel pump supplies up to 29,000 psi of fuel pressure to piezo electric fuel injectors. While the injection pump features an integral low pressure transfer pump, all Ford Transit vans equipped with the 3.2L Power Stroke also feature an electric fuel lift pump submerged in the fuel tank to ensure uninterrupted fuel flow and reliable fuel delivery.

Turbocharger

The 3.2L Power Stroke utilizes a Garrett variable geometry turbocharger and air-to-air charge air cooler (CAC). Vane position is controlled by means of an electric actuator, in lieu of the hydraulic systems employed in many previous Power Stroke engines. The turbocharger boasts an unfathomable maximum compressor speed of 197,800 rpm and is mounted directly to the exhaust manifolds on the passenger side of the engine.

Emissions Controls

Meeting emissions regulations at both the State and Federal levels requires that the 3.2L Power Stroke employ an exhaust recirculation system in addition to an exhaust aftertreatment methodology. The exhaust aftertreatment system consists of a diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) equipment. The DOC and DPF are arranged into a single unit common referred to as a single brick system (SBS). Advantages of a SBS system include minimized heat loss between the DOC and DPF and reduced packaging size.

Since the DOC and DPF share a canister, heat loss during regeneration is reduced as the flow path distance is minimized. One could argue that passive regeneration is more effective under certain conditions due to the heat containment between the two units. Unlike other Ford engines, the 3.2L Power Stroke utilizes a dedicated injector to introduce fuel into the DOC during active regeneration cycles. The alternate strategy requires fuel to be injected into the combustion chambers during the exhaust stroke and is known to cause excessive fuel dilution conditions.

3.2 Power Stroke Applications

The 3.2L Power Stroke's only application in North America is the 2015 to 2019 model year Transit 150, 250, and 350. Due to its relatively low power density (0.95 hp/CID), the engine was likely never a serious candidate for the Ford F-150. For comparison, the F-150's 3.0L Power Stroke's offered 1.37 hp per CID, 36% greater than that of the 3.2L. The smaller engine's ratings were also 65 horsepower and 90 lb-ft greater. Although the 3.2L Power Stroke likely has more potential than what it has been calibrated for in the Ford Transit van, the 3.0L ultimately proved more suitable for the F-150.

3.2 Power Stroke Engine Specs

Engine Oil Viscosity Chart

Fuel Economy

Ford is not legally required to evaluate or publish fuel economy figures for the 3.2L Power Stroke equipped Transit van due to its GVWR, which exceeds 8,500 lbs (Federal law dictates that vans with a GVWR in excess of 8,500 lbs are exempt from EPA fuel economy reporting regulations). The same rules relieve Ford from reporting fuel economy figures for its various Super Duty truck models.

Note that while actual fuel economy numbers will vary widely and be dictated by a great number of variables, Transit owners typically report figures in the 20-25 mpg range while traveling under highway conditions (long periods of driving at constant speed, minimal idle time) and 16-18 mpg of combined driving conditions (stop-and-go combined with highway conditions, some idling). Regeneration cycles and excessive idling tend to drag fuel economy figures down rapidly, so optimizing efficiency is widely dependent on driving conditions.

3.2 Power Stroke Horsepower & Torque Curves

One of the 3.2L Power Stroke's greatest advantages is arguably its relatively flat torque curve, which maintains at least 90% of peak torque (350 lb-ft) from 1,500 to 2,750 rpm. This generous operating range, with torque climbing rapidly off-idle and peaking near 1,500 rpm, translates to smooth acceleration characteristics under diverse driving conditions and payload weights.