Ford's 3.5L EcoBoost Evolution

In the dynamic world of modern turbocharged engines, few rival the transformative journey of Ford's 3.5L EcoBoost powerplant. From the groundbreaking Gen1 to the clean-sheet Gen2, and the present-day Gen3, each generation introduces advancements to improve power, fuel efficiency, and overall durability. This article dives into the evolution of the 3.5L EcoBoost engine, highlighting the technical achievements, known weaknesses, and Full-Race’s engineered solutions that address these issues.

In 2007, Ford put the automotive world on notice with an all-new twin-turbocharged, direct-injected V6 engine.  Designed to match the outgoing V8 in power while improving fuel economy by 15% - this engine was originally dubbed “TwinForce” when introduced on the 2007 Lincoln MK-R Concept Car and was later renamed to “EcoBoost” with the 2008 Lincoln MKT debut.  3.5L EcoBoost Production began in May of 2009 at Cleveland Engine Plant #1. The first commercially available vehicles to feature this all-new transverse (FWD) 3.5L EcoBoost V6 from Ford were the 2010 Police Interceptor (Taurus), Explorer Sport, Ford Flex, and Lincoln MKS/MKT.

In 2011 Ford went all-in on the EcoBoost initiative, with their all-new longitudinal (RWD) Generation 1 3.5L EcoBoost V6 powering the legendary F-150, proving itself in the highly publicized "Beat to Hell and Back" Baja 1000 torture test.

Based on the Duratec 3.5L 60-degree V6 aluminum engine, the EcoBoost 3.5L block is fortified for turbocharged life with 6-bolt press-fit main bearing caps and a forged-steel, fully counterweighted crankshaft.  It utilizes direct fuel injection at 2150 PSI for maximum knock resistance, fuel efficiency, and overall performance. Gen1 powered trucks feature twin BorgWarner turbochargers tuned to produce 15 PSI of boost. Despite the added boost, the first-generation EcoBoost V6 engines can run on regular-grade gas per manufacturer specs, but we recommend premium fuel to maximize reliability and performance for any turbocharged engine.

In 2011-2012, the early Gen1 3.5L F-150 engines were equipped with the smallest turbos in the lineup, and an integrated blow-off valve (BOV) on the turbo's compressor housing.  Hitachi provided these early 11-12 fuel systems.  The exhaust manifold was cast iron and fastened with mild steel studs, which were susceptible to warping and broken manifold studs causing exhaust leaks aka “EcoBoost chirping”, which is why we developed our Formline GEN1 EcoBoost Manifolds and inconel stud kit.

By 2013, Ford introduced significant updates to the 3.5L engine, carrying through until 2016.  These updates included larger turbos, an electronic BOV, and the transition to the Bosch direct injection fuel system. The final evolution of the Gen1 appeared on the 2017+ Transit van, which retained the foundation of the 2013-2016 iteration, while incorporating revised timing components and updated 6R80 transmission tuning.

At the core of the GEN1 engine’s reliability is its robust bottom end. It features a forged steel crankshaft with 6-bolt main bearing caps, ensuring durability under high stress. Steel rods are attached to cast aluminum pistons with a steel ring carrier, floating wrist pins, and a coated skirt, all designed to handle long-term boost. The oiling system is a traditional gerotor oil pump with fixed oil pressure. 

The cylinder heads use a shimless-bucket valvetrain that's proven to be exceptionally reliable. Finally, the timing system features one long primary timing chain and two secondary chains. It’s worth noting that the primary chain may stretch or wear over time–generally at or above 150,000 miles–and should be replaced with the updated Transit Van timing components.

GEN1 TECHNICAL HIGHLIGHTS:

• Forged Crankshaft: The Gen1 3.5L EcoBoost uses a reliable forged and fully counterweighted crankshaft with 6-bolt main bearing caps for strength and durability.  Later model Transit Vans used a Gen1 engine with the strongest Gen3 crank.

• Shimless Bucket Valvetrain: Similar to Toyota’s legendary 2JZ, the simple “DAMB” Direct-Acting-Mechanical-Bucket valvetrain design is found only on the Gen1 3.5L. The cam lobe pushes directly on the valve (there is no rocker) and this simplicity contributes to the engine's reliability and efficiency

• Short Runner Intake Manifold: Enhances the engine's responsiveness and performance.

• Gerotor Oil Pump: Traditional fixed oil pressure system providing consistent lubrication with no extra moving parts to complicate matters

• Metal Oil Pan: Ford used Aluminum oil pans on all Gen1 EcoBoost engines

• Bore x Stroke (in): 3.64 x 3.41

• Gen 1 3.5L Variations:  

  • 2011-2012: Smallest turbos with a blow-off valve (BOV) on the compressor housing, uses Hitachi fuel system.

  • 2013-2016: Larger turbos with an electronic BOV, uses Bosch fuel system.

  • 2017-2024+: Retained all features from the 2013-2016 versions with updated timing chain components and revised 6R80 transmission tuning.

Applications:

• 2011-2016 Ford F-150: 365 hp, 420 lb-ft of torque.

• 2015-2017 Ford Expedition, Lincoln Navigator: 380 hp, 460 lb-ft of torque.

• 2013-2024 Ford Transit Van: 310 hp, 400 lb-ft of torque.

Coolant Leaks from Jiffy-Tite Fittings

One of the most common reliability issues we’ve observed with these engines is the jiffy-tite coolant hardlines leaking as they age. Fortunately, Full-Race offers a solution to this issue with our upgraded GEN1 Turbo AN Coolant Line Kits enhancing the engine’s long-term reliability by eliminating the Jiffy fitting altogether.

Exhaust Manifold Warping or Cracking

The factory log-style exhaust manifolds on the GEN1 3.5L EcoBoost are cast iron and susceptible to warping and cracking - especially in heavy-duty and high-performance applications. This can lead to exhaust leaks, reduced performance, and that notorious “chirping” noise.  While cast iron works fine for diesel engines, it’s just not capable of handling gasoline’s 1750F exhaust gas temperatures long-term. Additionally, the use of mild steel studs to fasten the manifolds contributes to the problem, as they tend to stretch or break off at the head, further loosening the manifolds and requiring a challenging extraction. Upgrading to high-quality aftermarket manifolds, such as our Formline GEN1 F-150 Turbo Manifolds, and our Inconel Stud Kit provides a durable solution by using high end materials that withstand thermal stresses, reducing the risk of failure and improving overall performance.

Turbocharger Issues

BorgWarner is Ford’s exclusive turbocharger supplier for the F150’s 3.5L EcoBoost engine.  They’re robust turbos, capable of lasting hundreds of thousands of miles. Common issues include wastegate canister failure, boost pressure leaks, or even turbo failure, which results in reduced power, sluggish acceleration, or unusual noises such as whistling or grinding. For those looking to replace worn turbos, we offer two excellent options: the BorgWarner Stock Replacement Turbo Kit for those who want a reliable, OEM-like replacement, and the Formline Turbo Kit, designed for GEN1 3.5L owners looking to maintain reliability while increasing power output. Both options provide superior quality and durability compared to stock, ensuring long-lasting performance.

Intercooler Issues

The intercooler is typically the first mod an EcoBoost enthusiast should do - and for good reason. The OEM intercooler can heatsoak easily and is known for allowing condensation to form inside.  The Full Race front mount intercooler keeps charge air temps close to ambient and can evacuate moisture through the BOV at the lowest point in the system.  

Spark Plug Wear

As with any turbocharged engine, the EcoBoost demands a lot from its spark plugs. Misfires can occur if the spark plugs are worn/damaged or gapped too large, especially when running on lower-grade fuel. Upgrading to higher-quality spark plugs for your GEN1 3.5L EcoBoost can reduce the chances of misfires under boost.  And if you’re running a performance tune, closing the gap to 0.025 (or smaller) is recommended.

Cam Phasers and Timing Chain Stretch

Another well-known issue with this engine is valvetrain rattle, which typically occurs after 150,000 miles, and most commonly seen on the 2013-15 engines.  Symptoms include a rattling noise on startup, notably during cold-soaked engine start.  While many trucks may exhibit the cold start rattle for hundreds of thousands of miles without issue - once a code is set you’ll need to get the timing assembly replaced.  If left unaddressed, a failed timing assembly can lead to significant engine damage. Ford later revised the timing components in newer Gen1 engines found on the 2017+ Transit vans.  As called out in TECHNICAL SERVICE BULLETIN 18-2305 - retrofitting these newer parts into older trucks is recommended.

Carbon Buildup and Fuel-Diluted Oil

The GEN1 3.5L EcoBoost relies only on direct fuel injection, which improves efficiency and performance but can lead to fuel dilution and carbon buildup on the intake valves over time. Since the fuel doesn’t wash over the valves (as in port-injected engines), this buildup can reduce engine performance and fuel efficiency. The addition of a catch can system along with regular oil changes using a high-quality oil (like OEM Motorcraft) may help mitigate this issue.

The GEN2 EcoBoost engine marked a major overhaul aimed at improving both power delivery and efficiency.  GEN2 3.5L EcoBoost introduced a clean-sheet design that shared only bore and stroke measurements with the previous generation, bringing a host of improvements like dual injection, larger turbochargers with electronic wastegates, and upgraded cylinder head ports.  This all-new second-generation 3.5L twin-turbo EcoBoost V6 was paired with an all-new 10R80 10-speed automatic transmission, further enhancing performance and drivability.

Introduced at the 2015 Detroit Auto Show, this new engine was showcased in Ford’s storied carbon fiber supercar, the 2016+ Ford GT, which produced 647 hp. This was quickly followed by news of a massive $145 million investment in the Cleveland Engine Plant to support this new engine. Jimmy Settles, the UAW Vice President, National Ford Department said: “The team at Cleveland Engine is thrilled to begin building one of the most technologically advanced engines ever designed for the all-new F-150 Raptor.”

The GEN2 EcoBoost engine was a complete overhaul from the Gen1 engine. Despite having structurally similar bore spacing and rod length/stroke, almost every other component was redesigned for improved performance and reliability. 

One of the biggest changes between GEN1 and GEN2 EcoBoost V6 engines was the addition of a Dual-Injection fuel system, which combined direct injection (DI) and port fuel injection (PFI). This improves emissions, minimizes carbon buildup on intake valves, and increases the maximum amount of horsepower the engine can produce —all drawbacks of the Gen1’s direct injection only configuration.  The GEN2 system added six port injectors to the intake port operating at 60psi, in addition to the six direct injectors operating at 2400 PSI. The Bosch engine computer controls all 12 injectors independently, allowing the port and direct injection systems to work separately or in conjunction with each other. At low RPM or during cold start conditions, the engine operates solely on the port fuel injectors, reducing soot emissions.  Higher loads blend in additional fuel from the direct injection system.  From a horsepower standpoint, this much fuel headroom in an OEM configuration is an ideal scenario.  From a reliability standpoint, the port injectors spray fuel onto the back of the intake valves, helping to prevent carbon buildup (commonly seen in direct-injection-only systems of the Gen1).

The 2017 GEN2 EcoBoost also received many upgrades to its twin BorgWarner turbochargers.  Visibly recognizable are electronic stepper-motor wastegates ("E-Gates"), delivering precise control and higher boost capability compared to the soft Gen1 pneumatic wastegate spring. The GEN2 HO turbine wheels featured MAR-M-247 super-alloy material along with larger compressor wheels, and visibly sharper blade angles for improved response, efficiency, and performance. In 2018-2020 Ford went one final step further in refining the turbos with the addition of the highest flowing wheels across all GEN2 3.5L engines, in a ported-shroud compressor housing.

Of particular note, GEN2 3.5L saw Ford introduce a dual primary timing chain system, replacing the single chain in Gen1, which was prone to stretching over time. The new setup featured shorter, stronger chains with thicker side plates for enhanced durability. To accommodate the new dual chain system, the crank gear was also converted to a dual-drive sprocket. The cylinder heads received significant valvetrain upgrades starting with a roller-rocker and hydraulic lifter, similar to Ford's GEN2 Coyote 5.0L engine. These actuate larger diameter hollow stem intake valves and sodium-filled exhaust valves, each with triple valve locks. 

For the engine’s bottom end, Ford implemented a new block casting and a slightly stronger forged crankshaft. However, the connecting rods remained identical between GEN1 and GEN2. Compression ratios were 10.5:1 in the F-150 and lowered to 10:1 in the Raptor to accommodate the increased boost from the larger turbos on low grade fuel. The undersides of the pistons were redesigned to improve heat transfer back into the oil, and the introduction of piston-cooling oil jets added further durability. Similar to the Coyote engines, a variable-pressure oil pump reduces oil pressure based on engine demands; at idle and low loads oil pressure is reduced for fuel efficiency. Finally, an auto start/stop system was introduced to reduce emissions during city driving.

• Dual Injection System: Combines direct injection (DI) and port injection, allowing for greater performance flexibility and improved fuel efficiency. The DI operates at 2400psi (160bar).

• Larger Turbochargers, electronically controlled: Equipped with electronic stepper motor wastegates for better boost control and efficiency.

• Improved Cylinder Heads: Feature larger ports, hollow stem intake valves, and sodium-filled exhaust valves, similar to the GEN2 Coyote 5.0L engine.

• Dual Primary Timing Chain System: Stronger and more robust, addressing the timing chain stretch issues seen in Gen1.  Plastic timing chain guides were utilized

• Variable Pressure Oil Pump: Adjusts oil pressure based on engine demands for better lubrication and efficiency.

• Bore x Stroke (in): 3.64 x 3.41

• Compression Ratios:

• GEN2 High Output: 10:1 compression ratio

• GEN2 Standard Output: 10.5:1 compression ratio

• Turbocharger Variations:

• 2017: Smallest GEN2 turbos

• 2018-2020: Larger turbos with a ported shroud compressor inlet for increased airflow

The GEN2 EcoBoost V6 was offered across a range of Ford models, including the 2017-2020 Ford Raptor, F-150 Limited/Platinum, and as an option in other F-150 trims. The High-Output 3.5L GEN2 produced 450 horsepower and 510 lb⋅ft of torque - a considerable increase from the previous V8 powered Raptor’s 6.2L 411 horsepower V8 engine.  The Standard-Output 2017+ GEN2 EcoBoost was rated to 375 horsepower and 470 lb⋅ft of torque - although it has the same size turbos, and a higher compression ratio so it can actually make more power than the HO. Overall performance between the HO and non-HO variants is virtually identical, with the primary difference being the HO's dual exhaust system.

• 2017-2020 Ford F-150 Raptor and Limited HO: 440-450 hp, 510 lb-ft of torque.

• 2017-2020 Ford F-150 3.5L: 375 hp, 470 lb-ft of torque.

• 2018-2022 Ford Expedition / Navigator HO: 400 hp, 480 lb-ft of torque.

• 2018-2022 Ford Expedition / Navigator: 375 hp, 470 lb-ft of torque.

While the GEN2 3.5L EcoBoost introduced several improvements over the Gen1, there are still some common issues and failure points that owners should be aware of.

Coolant Leaks from Turbocharger Hardlines

The GEN2 3.5L EcoBoost is similar to the GEN1 in one frustrating way - leaks can still occur at the turbocharger coolant lines.  Ford decided to update the failure prone Gen1’s jiffy-tite fitting with a slip fit male/female rubber bushing.  Leaks at this rubber bushing can cause overheating and potential engine damage if not addressed, which is why we recommend upgrading to our GEN2 Turbo AN Coolant Line Kit to mitigate this issue once and for all.

Cam Phasers, Timing Chain and Valvetrain Components

The Gen2 engine is generally robust although if you go on youtube the HL3Z (2017-2020) cam phasers (aka cam gears) get all the attention.  The "HL3Z" GEN2 phasers can wear out prematurely, causing a distinct rattling noise. If this occurs, installing the  "ML3Z" cam phasers from the Gen3 2021+ engine can resolve the issue.  Most mechanics are unaware that replacing with the ML3Z (2021+) phasers is only part of the solution. There is a ton of compatibility between the Gen2 and Gen3 engines and since you're in there anyway it’s a good idea to swap your plastic timing chain guides and tensioner to the Gen3 “ML3Z” primary metal timing chain guides.   Furthermore, Gen3 EcoBoost actually uses the 5.0L Coyote “BR3Z”  lifters/rockers as a plug and play upgrade to the Gen2 3.5L.  See our list below with detailed part numbers 

Note: the last GEN2 engines produced in late 2020 and 2021-2022 Navigators featured the updated Gen3 Cam Phasers, Crankshaft and Coyote rockers/lifters.

Exhaust Manifold Stud Failure

The factory log style exhaust manifolds are fastened with mild steel one-time-use studs that can stretch and/or break off at the head, requiring a challenging extraction. Upgrading to high-quality aftermarket manifolds, such as our Formline GEN2 F-150 Turbo Manifolds, and our Inconel Stud Kit provides a durable solution by using high end materials that withstand thermal stresses, reducing the risk of failure and improving overall performance.

Turbocharger Issues

BorgWarner remains Ford’s exclusive turbocharger supplier for the GEN2 3.5L EcoBoost engine.  While they’re incredibly robust turbos, capable of lasting hundreds of thousands of miles, turbo failure can occur and is the perfect opportunity to upgrade to modern tech.  Symptoms like reduced power, underboost codes, sluggish acceleration, smoking exhaust, combined with unusual noises such as whistling or grinding should inspect the turbos. For those looking to replace worn turbos, the Formline Turbo Kit, is designed for GEN2 3.5L owners looking to maintain reliability while increasing power output. Both options provide superior quality and durability compared to stock, ensuring long-lasting performance.

Harmonic Balancer Crank Pulley

The GEN2 3.5L EcoBoost exhibits increased harmonics compared to the other engines.  The OEM harmonic balancer is a crank pulley that damps (reduces) vibrations throughout the engine.  Similar to the Coyote 5.0L engines, this crank pulley can wear over time and lose its ability to control damaging vibrations.  These can cause wear on the bottom end from the oil pump to the bearings and crankshaft.  Its a good idea to inspect your pulley and install a new one if cracked or worn - Gen2 Engine Crankshaft Pulley - HL3Z-6312-A.  Make sure to heat it up with a hot plate or similar before installing to make it an easy slip-on affair.  Do not use an impact gun on the crank bolt!

Plastic Oil Pans

The early 2017-2018 GEN2 3.5L EcoBoost came with a plastic oil pan to save weight.  This has a plastic drain plug that’s caused engine failure.  Most everyone agrees this is an awful solution, so in 2018.5 production Ford switched back to the Gen1 aluminum pan.  The early 17-18 trucks can be retrofitted with this pan but you must also change the oil pump pickup!!  Failure to do so will result in a damaged oil pump pickup and can cause oil starvation.

Spark Plug Wear

As with any high performance turbocharged engine, the GEN2 3.5L EcoBoost demands a lot from its spark plugs. Misfires can occur if the spark plugs are worn/damaged or gapped too large, especially when running on lower-grade fuel. Upgrading to higher-quality spark plugs for your GEN2 3.5L EcoBoost can reduce the chances of misfires under boost.  And if you’re running a performance tune, closing the gap to 0.025 (or smaller for high boost) is recommended.

Launched in 2021 Ford proved “Third time’s a charm” as they got the formula right with this third generation.  Gen3 EcoBoost V6  brings performance and reliability to a whole new level by refining the Gen2’s advancements and incorporating new and updated components to optimize strength, efficiency, emissions, and durability. With enhancements like a 250-bar fuel injection system, 5.0L Coyote valvetrain and the strongest piston/crank combination yet—all GEN3 engines are now built to the same internal specifications.  Notably absent are the High Output and Standard Output designations

Introduced in the 2021 model year, this engine built upon the advancements of the GEN2 while adding several new technologies designed to optimize power delivery, fuel efficiency, and emissions. Unchanged are the bore/stroke, head gasket, connecting rods, and oil/water pumps.  

Major improvements include the all-new and unique Gen3 block and heads, with “ML3Z” phasers, metal timing chain guides, new timing chain tensioners, along with a 3675psi / 250bar direct-injection fuel system.

The Harmonic Balancer receives a massive redesign and looks more like a racing car crank pulley. This necessitated Ford to relocate the AC compressor farther forward and that actually makes accessing and upgrading your Gen3’s turbos much easier.  

The turbocharger system received an update with rotary electronic wastegates that replaced the linear electronic wastegates used in GEN2.  In 2024, the turbo size was reduced to the smallest turbos used to date on the 3.5L F150 / Raptor.  <Rumor has it, this was done to keep the Raptor R noticeably faster>

Improving knock resistance by recirculating cooled exhaust gas into the engine is a modern solution for making increased power on low-grade fuel. One of the Gen3’s major upgrades is the Cooled Exhaust Gas Recirculation (EGR) system, which acts similarly to higher octane fuel. Cooled EGR is actually great for performance, helping increase power output without risking engine damage from detonation. 

It’s worth noting that some of these updates are backward-compatible upgrades for the GEN2.

• High-Pressure DI System: Operates at 3675 psi (250 bar), ensuring optimal fuel atomization and efficiency.

• Strongest Piston/Crank Combination: Designed to handle increased power levels from performance upgrades

• Updated Timing Chain Tensioners and Metal Guides: Bulletproof EcoBoost Timing components. Finally!

• Repositioned Ultra-High-Pressure Fuel Pump: Moved back to the driver's side (like GEN1) for improved harmonics.

• Improved Harmonic Balancer / Crank Pulley:  Massive Improvements to engine harmonics

• Compression Ratio: Consistent across all models for balanced performance.

• Cam Phaser: Ford finally got this right in Gen3 - ensuring durability and performance.

• Tuning: 2021-2022 Gen3 PCM’s are easily tuned.  For 2023 vehicles, most tuners must swap to a 21/22 PCM in order to tune.  2024 trucks can not be tuned at this time.

Ford’s 3.5L EcoBoost V6 has undergone rigorous evolution, addressing various power and durability challenges with each generation. While the Gen1 pioneered Ford’s foray into turbocharged V6 engines, each successive generation has introduced significant enhancements—from dual-injection fuel systems to electronically controlled wastegates and improved timing assemblies.

Full-Race’s targeted solutions address each generation’s unique vulnerabilities.  Our commitment to providing engineered upgrades that extend reliability and optimize performance will continue for the foreseeable future, ensuring that owners can confidently push their F-150s, Raptors, Transits, Navigators and Expeditions to their limits.