Ford 3.5 EcoBoost Engine Problems: 3 Most Common Issues

3.5 EcoBoost Twin Turbo V6 Engine

Ford introduced the 3.5-liter EcoBoost engine in the Lincoln MKS, MKT, Ford Flex, and Taurus SHO in 2010. The 3.5 liter twin turbo V6 engine was then integrated into a variety of other Ford and Lincoln models over the next few years. It’s a powerful engine with 355 to 647 hp and plenty of torque.

Additionally, turbocharging and direct injection assist the 3.5 V6 in remaining fuel efficient and emission-free. While the 3.5 EcoBoost is an excellent engine in general, no engine is perfect, and this is true here. We’ll discuss some of the most common issues with the Ford 3.5 EcoBoost V6 in this article, as well as its overall reliability.

Ford 3.5 Twin Turbo V6 Background

Before delving into 3.5 EcoBoost problems, it’s necessary to establish some context. The 3.5 EB comes in two distinct generations, which we will discuss briefly below. It’s critical to establish this for a reason.

Ford did an excellent job updating the second generation 3.5 EcoBoost engine. The updates aid in the support of increased power and torque. Additionally, they address a few reliability concerns, making the Ford 3.5 twin turbo engine from the second generation even more reliable.

1st Gen 3.5L EcoBoost

This is not to say that the first generation engine is a bad engine by any means. However, Ford pioneered the use of turbochargers, direct injection, and variable valve timing. There are always a few kinks to iron out, and they were relatively minor with the 3.5 V6. This will be discussed in greater detail in the upcoming discussion of common 3.5L EcoBoost engine issues.

In any case, the first generation EcoBoost produces 355-380 horsepower, depending on the vehicle. The smaller twin turbochargers are quick to spool and deliver a significant amount of low- and mid-range torque.

This makes the 3.5 EB an excellent engine for towing and fun around town without requiring full use of the engine’s RPM range. The 3.5 EcoBoost engine from the first generation is found in the following Ford and Lincoln models:

  • 2010-2019 Ford Flex
  • 2010-2016 Lincoln MKS
  • 2010-2019 Lincoln MKT
  • 2010-2019 Ford Taurus SHO
  • 2013-2019 Ford Explorer Sport & Platinum
  • 2011-2016 Ford F-150
  • 2015-2017 Ford Expedition
  • 2015-2017 Lincoln Navigator

2nd Gen 3.5 V6 EcoBoost

Ford began offering the second-generation EcoBoost engine in select models in 2017. It gains 375-450 horsepower in the majority of models. Ford, on the other hand, took it a step further by offering a 647hp variant of the legendary Ford GT. Naturally, that engine receives some upgrades over the standard 3.5 EcoBoost to accommodate the increased power.

Ford also added port injection to the second-generation 3.5-liter V6 twin turbo engines. This contributes to the prevention of carbon build-up, which we will discuss later in this article.

Additionally, Ford redesigned the timing chain in response to concerns about the previous design’s reliability. Another subject we’ll delve into. The engine from the second generation is used in the following models:

  • 2017-present Ford F-150
  • 2018-present Ford Expedition
  • 2017-present Ford F-150 Raptor
  • 2018-present Lincoln Navigator
  • 2017-present Ford GT

3 Common 3.5 EcoBoost Problems

3.5 EcoBoost Problems

With that background information out of the way, let’s get to the point. Several of the most frequently encountered issues with the Ford 3.5 EcoBoost engine include the following:

  • Carbon Build-up
  • Timing Chain
  • Ignition System

As mentioned previously, the top two issues primarily affect the first-generation 3.5 EcoBoost engine. Ford did an excellent job updating some of the engine’s weak points with the second generation engine. Again, the 3.5 EcoBoost is an extremely reliable engine in general. Two of the “issues” listed above may not even be considered issues.

Carbon build-up is simply a disadvantage of relying solely on direct injection. Parts of the ignition system such as spark plugs and ignition coils are also a disadvantage of turbocharging.

Having said that, we’ll delve deeper into these 3.5 EcoBoost issues below. Before we begin, let’s jot down a few quick notes. Simply because these issues are classified as common does not mean they affect a large percentage of 3.5 V6 engines.

Rather than that, they are a few of the most frequently encountered issues when something goes wrong. Additionally, engines are prone to a variety of other issues that we are not discussing – particularly as they age and mileage increases.

1) 3.5 EcoBoost Intake Valve Carbon Build-Up

Carbon build-up is primarily an issue with first-generation engines. The 3.5 EcoBoost engine from the first generation utilizes only direct injection (DI), which means fuel is sprayed directly into the cylinders. As a result, carbon accumulates on the intake valves over time. Every engine suffers from some degree of oil blow-by.

This oil eventually cakes onto the intake valves as it travels through the intake tract. The advantage of port injection is that fuel is washed over the intake ports and valves. This assists in removing oil deposits and preventing them from accumulating.

However, when only DI fuel is used, there is nothing to assist in cleaning the ports and valves. Carbon deposits accumulate over time and obstruct airflow into the cylinders. This is not a critical situation that requires immediate attention.

Certain DI engines can even run their entire lives without any valve cleaning. Carbon buildup, on the other hand, can result in power loss and a variety of other drivability issues.

Ford addressed this issue with the second-generation 3.5 EcoBoost by utilizing both direct and port injection. In many ways, it’s the best of both worlds, as DI has numerous advantages over PI. However, using PI has a few additional benefits, most notably assisting in the prevention of carbon build-up.

Ford 3.5 TT V6 Carbon Build-Up Symptoms

Excess carbon build-up on the 3.5 EcoBoost intake valves and ports manifests itself in the following ways:

  • Misfires
  • Rough idle
  • Stuttering/hesitation
  • Power loss

The majority of these symptoms are caused by the primary symptom – misfires. Carbon deposits can result in cylinders receiving an uneven amount of air. This disturbs the air-fuel mixture, which may result in the 3.5 EB misfiring.

As a result, symptoms such as fault codes, a rough idle, and stuttering may occur. Another frequent symptom of carbon buildup on the Ford 3.5L turbo engine is decreased power.

However, because carbon build-up occurs over time, it is frequently difficult to detect. Most likely, you will be unaware of a gradual loss of power over a period of several years.

3.5L EcoBoost Carbon Build-up “Fix”

Once the carbon deposits become excessive, walnut blasting the intake ports may be necessary. A high-quality shop vac and walnut media shells are required for this job. Otherwise, it’s primarily labor associated with gaining access to the intake ports. Shops frequently charge between $400 and $600 for this service, so it’s not exactly inexpensive.

Fortunately, this is not a time-sensitive task that requires immediate attention, and you may not even want to do it at all. Carbon deposits should not pose a serious threat to the 3.5 EcoBoost’s longevity. Regardless, we would want to complete the job. Walnut blasting should be performed every 70,000 to 100,000 miles as preventative maintenance.

2) Ford 3.5 EcoBoost Timing Chain Problems

Ford 3.5 EcoBoost Timing Chain Problems

Specific information about the Ford 3.5 timing chain problems is scarce. This is primarily a problem with first-generation engines. More precisely, it appears to affect primarily 3.5 EcoBoost engines manufactured between 2010 and 2014.

Ford enhanced the component before redesigning it for the second generation 3.5L twin turbo V6. Additionally, timing chain issues appear to be more prevalent on F-150 models than on others. However, it is entirely possible that this is simply because the F-150 is the most popular model equipped with the EcoBoost engine.

In any case, the issue at hand is one of timing chain stretching. Additionally, issues with the 3.5 EcoBoost timing chain guides, tensioner, and cam phasers occur. If an issue does occur, it is prudent to replace the entire timing chain assembly.

Fortunately, Ford issued a service bulletin in response to these issues. If your vehicle is no longer under warranty and you experience timing chain issues, you may be able to work with Ford.

These are typically urgent issues that should be addressed immediately. If the timing chain completely fails, additional damage to the 3.5 EcoBoost engines is possible. Although this is a very rare occurrence, it is critical to repair the timing chain promptly if problems arise.

Ford 3.5L Timing Chain Symptoms

On the 3.5 EcoBoost, some symptoms of timing chain, guide, tensioner, and cam phaser failure include the following:

  • Cold start rattle
  • DTC P0016
  • Check engine light
  • Drivability issues

Rattling on cold starts is one of the more common symptoms of a timing chain problem. However, numerous other factors can cause rattle. Additionally, the 3.5 EcoBoost may generate the P0016 fault code, which will illuminate the check engine light.

Finally, when the timing chain stretches, it can throw off the ignition timing, resulting in drivability problems. This includes misfires, power loss, and a rough idle, among other things.

3.5 Twin Turbo V6 Timing Chain Replacement

Replacing the timing chain and other critical components is not a simple or inexpensive task. It’s time consuming and the component costs can add up. Additionally, while you’re in there, consider replacing a few other small items. Timing chain replacement is likely to cost in the thousands of dollars range.

Many faulty 3.5 EcoBoost timing chains, on the other hand, were almost certainly replaced at some point. While this is a common issue with the EcoBoost, it does not occur with every engine. Some believe it is due to insufficient maintenance and oil changes, or to the use of 20w oils, which are too thin for the engine.

Ford has also issued bulletins, indicating that they are fully aware of the timing chain issues. Even if the repair is not covered under warranty, you may be able to negotiate a discount or other form of compensation with Ford.

3) Ford 3.5 V6 Spark Plug & Ignition Coil Issues

Ford 3.5 V6 Spark Plug & Ignition Coil Issues

To be honest, this is mostly here because we’ve run out of other topics to discuss regarding the 3.5 EcoBoost. To refer to spark plugs and ignition coils as a “issue” is probably not accurate. It is, however, inherent in owning a twin turbo, direct injected engine.

We are very familiar with this coming from the BMW world. Turbocharged engines place a great deal of strain on the ignition system, owing to the incredibly high cylinder pressures.

On naturally aspirated engines, spark plugs frequently last over 70,000 miles, while ignition coils typically last about twice that. However, the ignition components on the 3.5 twin turbo EcoBoost engine are likely to wear out much more quickly.

Often, it is simply normal wear and tear, but early problems are possible. This is fairly standard procedure for any engine, and the Ford 3.5L V6 is no exception.

Ignition components can produce a wide variety of symptoms and drivability issues, so don’t overlook simple spark plugs or coils. Spark plugs for stock 3.5 EcoBoost engines will likely need to be replaced every 40,000 to 60,000 miles. Ignition coils should last approximately twice as long.

If you’re running a tune, making mods, or driving the 3.5 EcoBoost hard, the lifespan of the ignition components can be significantly reduced. Every 10,000 miles, our twin turbocharged 335i with the N54 engine requires new spark plugs. Ignition coils have a life expectancy of 25,000 miles – if we’re lucky.

3.5 EB Spark Plug & Ignition Coil Symptoms

Symptoms of a spark plug or ignition coil on the verge of failure include the following:

  • Misfires
  • Rough idle
  • Stuttering
  • Check engine light (misfire codes)

Typically, plugs and coils exhibit the same symptoms. We typically recommend replacing all six spark plugs or ignition coils at the same time; this is especially true if they haven’t been changed in a while. If you’re experiencing misfires, here’s an easy way to determine whether the problem is with the spark plug or coil.

Determine which cylinder(s) is misfiring by inspecting the fault codes. Remove the ignition coil from that cylinder and replace it with one from a non-misfiring cylinder. If the misfire persists after installing the new cylinder, you’ve identified the source of the problem.

If this does not work, repeat the procedure using the 3.5 EcoBoost spark plugs. You may also consider simply replacing the spark plugs. It’s a simple and inexpensive repair.

Ford 3.5L Plugs & Coils Replacement

Again, the method outlined above is an effective way to ascertain the source of the problem. Often, spark plugs are to blame, as their lifespan is significantly shorter than that of ignition coils.

Fortunately, a set of six Ford 3.5 spark plugs typically costs between $40 and $100, depending on the source. It’s a simple task that almost anyone can complete in less than an hour or two in their driveway.

A set of ignition coils costs between $200 and $300. However, it is a much simpler job than changing the spark plugs. Repair this yourself or, if you prefer, have it done by a repair shop. Labor should cost less than $100.

Ford 3.5 EcoBoost Reliability

Is Ford’s 3.5-liter EcoBoost engine dependable? Yes. The Ford 3.5 twin turbo engine, we believe, receives above-average reliability ratings. There aren’t many issues that frequently occur with these engines. Additionally, Ford did an excellent job with the second-generation 3.5 EcoBoost in addressing some of the issues.

Of course, the reliability of each 3.5 V6 engine is partially determined by luck of the draw. It is one of the variables over which we have no control. However, you have some control over how well the twin turbo EcoBoost engine is maintained. Change the oil on time, use high-quality oils, and address issues as they arise.

Take care of the 3.5 EcoBoost and it will almost certainly reward you with a pleasant, reliable driving experience. Turbo engines do require some additional maintenance, but we believe it is worthwhile in the long run.

Ford EcoBoost engines deliver exceptional performance, torque, fuel economy, and towing capacity. The majority of 3.5L V6 EcoBoost engines should have no significant issues reaching 200,000 miles or beyond. Not too shabby in terms of longevity.

3.5 EcoBoost Common Problems Summary

To be fair to the Ford 5.0 Coyote engine, we believe the 3.5 EcoBoost is a clear choice if offered. The Ford 3.5 EB strikes an excellent balance of power, torque, towing capacity, and efficiency.

Additionally, the use of twin turbos provides an abundance of tuning potential for those looking to get the most out of their engines. Although we adore the 3.5 EcoBoost, no engine is perfect.

Earlier generations of gen 1 engines encountered issues with timing chain failure and carbon buildup. While timing chain issues are unlikely to be as prevalent as some may believe, they are something prospective owners should be aware of.

Additionally, direct injection causes carbon deposits on the intake valves, which can cause drivability issues. Ford did an excellent job of addressing these issues once they became aware of them.

Otherwise, it’s worth noting that turbo engines can be a little more difficult to maintain. Due to the high turbo boost pressures, spark plugs and ignition coils are subjected to significant abuse. Additionally, turbocharged engines, such as the Ford 3.5 EcoBoost, have more components that could fail.

Nonetheless, turbo technology has advanced significantly over the last few decades. Maintain the Ford EcoBoost engine properly, and it will almost certainly reward you with a dependable, enjoyable driving experience.

What are your thoughts on the 3.5 EcoBoost? Leave a comment and inform us!

Up Next: Ford 1.5 EcoBoost Engine Problems: The 4 Most Common Problems

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