Ford’s 2.5L Duratec engine, also known as the Duratec 25, is a naturally aspirated inline-four cylinder engine used from 2009-2019. The I4 Duratec was built in partnership with Mazda, and is based off of the Mazda L5 engine. The 2.5 Duratec produced 156-175hp and 136-172lb-ft. of torque. Ultimately the 2.5 Duratec was retired in 2019 in favor of Ford’s new EcoBoost engine family.

The 2.5 Duratec was a base model engine for the Fusion and Escape cars. The 1.6 EcoBoost and 2.0 EcoBoost were available as upgrades, offering more power.

Ford and Mazda also teamed up in the early 1990’s to produce the 2.5L Duratec V6 engine. Despite using the same Duratec 25 engine name, the I4 and V6 versions of the engine are completely different and were used in separate vehicles. The Duratec V6 was produced from 1994 until 2002 and was predominantly an international engine used in the Ford Mondeo.

This common problems guide focuses specifically on the I4 Duratec 25.

With a max output of 175hp, the 2.5 Duratec often gets overlooked due its minimal power. While it may not be an engine for a true auto enthusiast, it’s an excellent choice for those looking for a reliable and fuel efficient engine to get from point A to point B.

2.5 Duratec I4 Vehicle Applications

• 2009-2019 Ford Escape
• 2010-2019 Ford Fusion
• 2010-2013 Ford Fusion Hybrid
• 2014-2018 Ford Transit Connect
• 2011 Lincoln MKZ Hybrid
• 2010-2013 Mercury Milan
• 2010-2011 Mercury Milan Hybrid

Ford 2.5 Duratec I4 Common Problems

I had an extremely difficult time finding any common problems on these engines. I have heard the term over-engineered used for the Duratec I4. While I won’t disagree, it’s extremely difficult to break a piston or run into issues with the engine internals, block, etc. when you have 2.5L only putting out 175hp. This is great news for reliability and my inability to find major problems with this engine is a testament to its longevity.

1. Excessive Coolant Consumption
2. Transmission Hard Shifting
3. Power Steering Failure

1. 2.5 Duratec Excess Coolant Consumption

The most common “problem” with the Duratec I4 is its propensity to guzzle engine coolant. Most owners claim having to refill on coolant once to twice per year whereas most cars typically only need a coolant top off every few years, if at all.

There hasn’t really be any conclusive reason for why the Fusion and Escape’s consume so much coolant. However, it isn’t typically caused by any sort of noticeable coolant leak which has led some to believe that the cause is engine block porosity.

While there isn’t a solution we know of to this problem, it’s important to be aware of the issue. If you run low on coolant the engine can overheat. When an engine overheats it can warp the engine block, heads, and internals and lead to catastrophic engine damage. We recommend keeping an extra bottle of coolant in your trunk in case you see the low coolant warning light in the middle of a trip.

Outside of the mysterious coolant loss, there are a number of other potential causes of coolant loss. A cracked radiator, leaking water pump or hoses, blown head gasket, or cracked heads can all cause significant coolant loss.

Symptoms of Coolant Loss

• Low coolant warning light
• Engine overheating
• Possible coolant leaks

Potential Causes of Coolant Loss / Leaks

• Cracked / leaking radiator
• Bad radiator cap
• Blown water pump
• Leaking hoses
• Blown head gasket
• Expansion tank failure

2. Transmission Shifting Problems – Duratec 25 I4 

The transmissions in the Fusion, Escape, and Milan use a traditional 6-speed automatic. Unfortunately, the transmissions have leaking issues which causes the trans fluid to run low and lead to numerous issues like hard shifting, erratic shifting, slippage, etc. On the 2012-2014 Fusion’s and Escape’s the issues are likely to start arising around the 70,000 mile mark.

While these problems are most prone on 2012-2014 cars, we have seen issues reported with all years. The common cause of the issue is a leaking shaft seal, located on the left side of the transmission. The output shaft seal is located on the front of the transfer case and is responsible for sealing the output shaft to the transfer case. As is common with seals overtime, they wear out and deteriorate which causes transmission fluid to leak out at the output shaft.

A second common cause of transmission problems in these cars is caused by the powertrain and transmission control modules. The software calibration can fall out of sync and need to be upgraded. When the TCM/PCM is the issue you will typically notice rough or delayed shifting between gears 1 and 2 and between 4 and 5.

The most telltale sign is tranny fluid leaking from the transfer case. However, a lot of 2.5 Duratec owners don’t notice the leaks until it is too late. Once enough fluid leaks out, the transmission becomes highly problematic experience issues from rough shifting to gear slippage.

First, check your transmission fluid and transfer case for any leaks. If there are no leaks and fluid looks good, then the likely issue is with the PCM/TCM. However, read on below as a TCM or PCM upgrade can lead to further transmission problems.

Leaking Transmission Fluid Symptoms

• Fluid leaking from transfer case
• Hard shifting
• Gear slippage
• Delayed shifts

Replacement / Prevention Options

Ford’s solution to these issues is reprogramming or upgrading the software on the powertrain control module and transmission control module. However, there are some mechanics who claim that the software update is just a band aid and causes larger fluid leaks which can lead to clutch and total transmission failure.

The transmission software update increases pressure within the transmission to prevent leakage. However, the increased pressure creates additional wear and tear on the output shaft seal, leading to larger fluid leaks over time. While it is a viable solution in a handful of vehicles, make sure you are not leaking fluid already. If you are leaking fluid, replace the output shaft seal instead of simply reprogramming the control modules.

The simplest way to prevent issues and ensure transmission longevity is to make sure you always have adequate levels of trans fluid in the transmission.

3. Power Steering Failure – Fusion & Escape

While this problem again isn’t necessarily engine focused, it is a potentially dangerous issue for Ford Fusion and Escape drivers. Ford replaced the hydraulic power steering units with new electronic power assister steering (EPAS) units. The new system simplified power steering in the sense that it removed all the pump, pulleys, and fluids needed for hydraulic systems. However, it complicated it in the sense that the whole system is now controlled by computers.

The new EPAS system has a motor, ECU, torque sensor, and steering wheel position sensor controlling the system. The issue with the EPAS system in the 2.5 Duratec is that the torque sensor is prone to sudden failure. The torque sensor monitors how hard and how far you have turned. This sensor is the primary failure point and usually fails instantaneously without any warning lights or heads-up.

When the sensor fails it no longer sends a signal to the ECU and the ECU then disables the power steering unit. Ultimately, you will lose power steering and have a really difficult time turning the wheel, especially at slow speeds.

Torque Sensor Replacement

Unfortunately the repair isn’t as simple as just replacing the torque sensor. The torque sensor is built directly into the steering column and therefore cannot be replaced without pulling the steering column. Fortunately, this issue became a recall item for the majority of models with the 2.5 Duratec.

2.5 Duratec I4 Reliability

As I mentioned above, finding common problems for the Duratec 25 was rather difficult. While these engines lack power, the tradeoff is fantastic reliability. It is hard to bust a lot of systems when you are pushing 175hp in a 2.5L engine making this engine extremely reliable.

There are virtually no common problems associated with this engine by itself. The Fusion and Escape’s using it have had some transmission and power steering issues but overall nothing in particular has plagued the engine. They are known to guzzle coolant so just make sure you frequently top off on coolant as needed.

There aren’t many performance modifications available for the Ford 2.5 so it is hard to say how reliable these are with added power. However, we can say for certain that these engines are extremely reliable when kept stock and used simply for getting from point A to B.

Yes they are extremely reliable but maintenance is to be expected with age. Once you surpass the 100k mile mark and make your way towards 150k, you can expect some basic repairs to pop up eventually like water pumps, spark plugs and ignition coils, fuel injectors, gaskets and seals, suspension components, etc.

A well maintained 2.5 Duratec can last 250,000+ miles.