Ford 3.5L EcoBoost Engine (Specs, Reliability & Issues)
Updated: May 2
The 3.5L EcoBoost is a turbocharged, direct-injected 3.5-liter V6 gasoline engine that was first introduced in 2007 as the TwinForce. This engine's main purpose was to give a viable alternative to a large-displacement V8 engine like the V8 coyote derived engine.
The new turbocharged 3.5L V6 engine generates the same power and torque as a naturally aspirated 6.0L V8, but uses less fuel and releases less harmful substances into the environment.
The popular base for this V6 engine has become Ford's best-selling vehicle - the Ford F-150 - since its launch in 2009 and continuous usage in Ford cars.
Given that EcoBoost F150s are less priced than V8 F150s and don't have the downsides of small displacement, NA 6-cylinder engines, this isn't surprising. Let's take a closer look at the 3.5 EcoBoost engine, including common problems, reliability, and longevity.
The Duratec 35 (Ford Cyclone V6) engine block has the same diameter and stroke specs as the Ford Cyclone V6 engine. With an open deck and high-strength steel sleeves, the EcoBoost block is completely constructed of aluminium.
The engine has forged steel I-beam connecting rods and a forged steel crankshaft with 6-bolt main bearing caps. High-strength aluminium and CNC machined pistons have a low friction coating on the piston skirt and a well fitted piston top shape for optimal combustion.
Oil jets spray oil onto the bottom of the pistons in the cylinder block, keeping them cool and strong. An oil pan is also made of aluminium.
The 3.5L EcoBoost engines include aluminium cylinder heads with four valves per cylinder, pent-roof combustion chambers, centrally positioned spark plugs (iridium spark plugs), and two overhead camshafts. The fuel injectors for the GDI system are located below the intake valves.
The sizes of the intake and exhaust valves are 37 mm (1.456 inches) and 31 mm, respectively (1.220 inches). In the valvetrain, solid polished buckets are employed - Direct-Acting Mechanical Buckets (DAMB). The camshafts are driven by a single main chain.
Ford employed Twin Independent Variable Camshaft Timing on this engine (Ti-VCT). In the direct fuel injection system, a lobe on the driver's side of the intake camshaft powers a high-pressure fuel pump. The pump can provide a fuel pressure of up to 2150 psi.
A turbocharger is a crucial component that contributes to the vehicle's outstanding performance. Twin parallel mounted Borg Warner K03 turbochargers are utilised in the truck type, however Garrett GT15 turbochargers are used in other applications.
They're variable-vane turbos with low pressure that attain peak torque faster (at just 2,500 rpm) and decrease turbo lag. It delivers 90% of its peak torque between 1,550 and 5,500 rpm. Turbochargers are attached to high-strength cast iron low-volume exhaust manifolds.
After turbochargers, exhaust gases travel via rapid cat-converters to reduce emissions. The intake manifold, charge pipes, and OEM intercooler end tanks are all made of plastic.
A Coil-On-Plug (COP) distributorless electronic ignition system, a powerful Bosch engine computer unit, high-precision knock sensors, IAT sensors, MAP sensors, wideband O2 sensors, and more are among the modern electronic components.
Gen-2 3.5L EcoBoost Engine
In 2017, Ford revised the 3.5L EcoBoost engine, making a new, more powerful version available for the 2017 F-150, 2018 Expedition, and 2018 Navigator. Multi-port fuel injection and new turbochargers are two of the most prominent modifications to the enhanced engine.
Multi-port fuel injection is used in conjunction with direct injection to fulfil higher fuel output demands while also reducing carbon buildup on the intake valves, enabling the engine to retain its performance over long distances.
The new Borg Warner turbocharger has a MAR-M-247 super alloy turbine wheel as well as an electronically regulated wastegate, which significantly decreases turbocharger lag.
The core mechanism of the new 3.5 EcoBoost is made up of two chains (there is one separate timing chain driving each cylinder bank). The cam chain drive sprocket on the crankshaft is a twin gear design. The new chains are more durable and less prone to straining since the side plates have been reinforced.
Cylinder heads now come standard with roller-finger follower valvetrains and light hollow camshafts. All of these changes are aimed at lowering friction and mechanical losses. Finally, the compression ratio was increased from 10:1 to 10.5:1. (excluding H.O).
Manufacturer: Cleveland Engine Plant No 1, Ohio, the USA
Production years: 2009-present
Cylinder block material: Aluminium
Cylinder head material: Aluminium
Fuel type: Gasoline
Fuel system: Direct injection, Direct injection + port injection
Number of cylinders: 6
Valves per cylinder: 4
Valvetrain layout: DOHC
Bore: 92.5 mm (3.64 in)
Stroke: 86.6 mm (3.41 in)
Displacement: 3,496 cc (213 cu in)
Type: Four-stroke, turbocharged
Compression Ratio: 10:1, 10.5:1 - 2017+ (except on the 3.5L EcoBoost HO for the Raptor, which remains at 10:1)
Power: 320-647 hp (239-482 kW) at 5,000-6,250 rpm
Torque: 350-550 lb-ft (475-475 Nm) at 2,250-5,900 rpm
Firing order: 1-4-2-5-3-6
Engine oil weight: SAE 5W-30
Engine oil capacity: 5.9 litres (6.2 qt) - with oil filter
Oil change interval: 9,000 miles (15,000 km) or 12 months
Applications: Ford F-150, Ford F-150 Raptor, Ford Expedition/Expedition EL, Lincoln Navigator/Navigator L, Ford Transit, Ford Flex, Ford Taurus SHO, Ford GT, Police Interceptor Sedan, Ford Explorer Sport, Ford Police Interceptor Utility, Lincoln MKS, Lincoln MKT
Problems & Reliability
In terms of reliability, the 3.5-liter EcoBoost has shown to be a reliable performer. Thousands of EcoBoosts have been driven without breaking down, and they're still running strong. No engine, however, is without defects.
Let's take a look at some of the most common problems and breakdowns, as well as the general reliability of the 3.5 EcoBoost.
This issue is most common in first-generation 3.5 EcoBoost engines built between 2010 and 2014, and it concerns timing chain strain.
The most common symptoms that indicate timing chain troubles include cold start rattling, drivability concerns, check engine light (MIL), and OBD P0016 error code. Turbocharged engines put a lot of strain on the engine oil.
The durability of these engines is greatly improved by following the oil change interval recommended (and even shortening them). Wear-out oil, as well as a faulty timing chain, may impair the 3.5 EcoBoost timing chain guides, tensioners, and cam phasers.
The timing chain and other components must be replaced, which is a time-consuming and costly process. The cost of the components may also add up. If a problem does occur, it is recommended that the whole timing chain assembly be replaced.
Ford released a service bulletin to address these concerns, and you may be able to work with them even if your car is no longer under warranty.
This carbon build-up issue, like the previous one, is primarily a concern on the first-generation 3.5 EcoBoost. All engines with direct fuel injection suffer from carbon build-up on the rear of the intake valves and on the walls of the intake ports.
Direct-injected engines lack a natural intake cleaning mechanism, while port injection systems flow fuel before intake valves to help wash away oil deposits and prevent them from accumulating.
Over time, carbon deposits build up, reducing airflow into the cylinders. The result is a loss of power, increased fuel consumption, a rough idle, engine misfires, and stuttering or hesitation.
The second-generation 3.5 EcoBoost features reduced valve carbon build-up and employs both direct and port injection. It's worth noting that this issue does not impact all first-generation 3.5 EcoBoost engines.
It is possible for some engines to go their whole lives without ever having their intake valves cleaned. If the carbon deposits get too thick, however, blasting the intake ports is a costly process. Cleaning the carbon build-up is advised every 70,000 to 100,000 kilometres in general.
Ignition Coils & Spark Plugs
The ignition system and its components are placed under a lot of stress by the nature of a twin-turbo, direct-injection engine. Stock spark plugs last 40,000 to 60,000 kilometres in non-modified 3.5 EcoBoost engines. The ignition coils should last nearly twice as long as the ignition coils.
Is This a Reliable Engine?
There's no reason to think otherwise. With these engines, there aren't many difficulties that develop often. To summarise, the 3.5 EcoBoost engine is a solid performer with a nice balance of power, torque, and efficiency.
Ford learned from their mistakes and dramatically improved their 2nd-generation engines. As a consequence, the bulk of the reliability concerns are restricted to the 3.5 EcoBoost's initial generation.
Keep in mind that turbo engines need a little more maintenance. According to independent research, the Ford 3.5 twin-turbo V6s have a long lifetime, lasting up to 200,000 miles or more if owners follow the recommended maintenance schedule, use the proper oil, and fix any faults as soon as possible.