What is the most reliable Ford diesel engine?

The short answer: Ford's 7.3-liter Power Stroke, produced from 1994 to 2003, is widely regarded as the most reliable Ford diesel engine.

For context, reliability is judged by durability, maintenance costs, and long-term ownership experience. The 7.3L has earned its reputation through decades of real-world use, ease of maintenance, and a proven track record in demanding work applications.

Why the 7.3L Power Stroke stands out

Here are the primary reasons enthusiasts and technicians cite when naming the 7.3L Power Stroke as the most reliable Ford diesel engine.

• Durable, time-tested architecture: a robust block and proven internals designed for heavy-duty use.


• Simple, proven fuel system: a reliable high-pressure oil system driving unit injectors with relatively few fragile electronics compared to later engines.


• Long track record of real-world longevity: numerous examples of trucks with 400k–500k miles and beyond with proper maintenance.


• Ease of maintenance and abundant parts availability: widespread aftermarket support and readily available OEM components help keep repairs predictable and affordable.


• Strong community knowledge and maintenance culture: decades of owner experience translate into shared best practices and cost-effective fixes.

These attributes contribute to a broad consensus in owner communities, shop manuals, and enthusiast media that the 7.3L Power Stroke is the reliable benchmark among Ford diesels.

Alternative candidates and caveats

While the 7.3L is widely praised, other Ford diesel engines have their advocates. No engine is immune to wear, and reliability can hinge on maintenance history, usage, and environment. Here are notable alternatives and considerations.

• 6.7L Power Stroke (2011–present): Modern and generally reliable, with improved emissions controls; more complex and potentially costlier to repair, but often praised for overall reliability in newer trucks.


• 6.0L Power Stroke (2003–2007): Had early reliability concerns related to cooling, injectors, and EGR; many issues addressed through upgrades, but it’s generally viewed as less reliable than the 7.3.


• 6.4L Power Stroke (2008–2010): Known for higher maintenance needs and emissions-system challenges; typically considered less reliable than the 7.3 and 6.0 in standard ownership experiences.


• Older 6.9L and 7.3L IDI (non-Power Stroke, pre-1994): Extremely durable, with simpler systems, and favored by some for reliability and simplicity, though they deliver far less power and modern efficiency.

In practice, owners who prioritize reliability often choose the 7.3L Power Stroke for work trucks and conversions, while newer engines offer improvements in power, efficiency, and emissions at the cost of greater complexity and potentially higher maintenance expenses. Reliability ultimately depends on how well the engine has been maintained and used.

Maintenance tips to maximize reliability

Whether you own a 7.3L or another Ford diesel, consistent, proactive maintenance is widely cited as the difference between a high-mileage, dependable vehicle and one that develops costly issues early in life. The following guidelines reflect common industry and owner sentiments.

• Follow OEM service intervals for oil changes, filters, and coolant; use diesel-rated oil and high-quality filtration.


• Maintain cooling system integrity to prevent head-gasket issues and overheating; monitor coolant condition and system pressure.


• Keep the fuel system clean and free of contaminants; replace aging lines as needed and source clean, quality fuel.


• Inspect turbo, intercooler, and emissions components regularly to prevent buildup and performance degradation.

Adhering to a disciplined maintenance regimen is frequently cited as the best way to sustain reliability and extend the life of any Ford diesel, especially older platforms.

Summary

Across Ford’s diesel lineup, the 7.3L Power Stroke remains the standout for reliability in widely owned, work-oriented trucks. Its rugged construction, relative simplicity, and documented longevity have solidified its status as the benchmark against which Ford diesels are measured. While newer engines offer gains in power and emissions control, they tend to come with greater complexity and repair costs. For buyers and owners prioritizing reliability above all, the 7.3L Power Stroke continues to be the go-to reference point.

Which is better, 7.3 gas or 6.7 Power Stroke?

The main differences are that the 6.7L diesel engine offers significantly more torque and better fuel efficiency (especially when towing), while the 7.3L gas engine is cheaper to purchase, lighter, and has more horsepower at higher RPMs. The best choice depends on your needs: choose the 6.7L diesel for heavy-duty towing and commercial use, and the 7.3L gas for lighter towing and general use where lower upfront costs are prioritized.
 
This video explains the performance difference between 6.7L diesel and 7.3L gas engines in Ford Super Duty trucks: 47sJB ReviewsYouTube · Nov 19, 2023
6.7L Powerstroke Diesel 

• Performance: Has substantially more torque, making it ideal for heavy-duty towing and hauling. 
• Fuel Efficiency: Gets better average fuel economy compared to the gas engine, though fuel costs can be higher. 
• Cost: Has a higher initial purchase price. 
• Maintenance: Can have higher maintenance costs and requires exhaust fluid (DEF). 
• Driving Experience: Less prone to "hunting" for gears when towing up hills. 
• Ideal For: Towing very heavy loads (14,000 lbs or more) or frequent commercial use. 

You can watch this video to see how the 6.7L diesel engine performs when towing heavy loads: 45sJB ReviewsYouTube · Nov 12, 2023
7.3L Godzilla Gas 

• Performance: Has more horsepower at higher RPMs, but significantly less torque than the diesel. 
• Fuel Efficiency: Lower fuel efficiency compared to the diesel, especially when towing. 
• Cost: Cheaper to purchase upfront. 
• Maintenance: Generally has lower maintenance costs and no need for DEF. 
• Driving Experience: Can feel underpowered when towing heavy loads and may require more gear-shifting. 
• Ideal For: Lighter towing (around 10,000 lbs) or general use where lower purchase cost is a priority. 

This video compares the 7.3L gas engine with the 6.7L diesel engine for truck owners: 58sT & T Landscape & MasonryYouTube · Dec 10, 2022

Which is better, 6.7 Cummins or 6.7 Power Stroke?

Neither the 6.7L Cummins nor the 6.7L Powerstroke is definitively "better," as the best choice depends on your priorities. The Cummins is generally favored for heavy-duty towing and long-term durability, while the Powerstroke often excels in everyday performance, with better fuel efficiency and responsiveness. 
This video compares the 6.7 Powerstroke and 6.7 Cummins engines: 43sGetty's GarageYouTube · Jul 9, 2023
6.7L Cummins 

• Best for: Heavy-duty towing and longevity. 
• Strengths:
  • Known for high torque at lower RPMs, which is ideal for towing. 
  • Has a strong reputation for long-term durability. 
• Weaknesses:
  • Can be more sluggish from the factory compared to the Powerstroke. 
  • Some model years may have specific issues, such as exhaust manifold problems in trucks that frequently tow or potential lifter failures. 

6.7L Powerstroke 

• Best for: Everyday driving, high-speed performance, and responsiveness. 
• Strengths:
  • Often has better fuel economy in highway and daily driving. 
  • Provides quicker acceleration and more horsepower out of the box. 
  • Generally considered smoother, with less vibration. 
• Weaknesses:
  • Tuning can lead to reliability concerns with the turbocharger's ball bearings over time. 
  • While robust, some mechanics note that pushing the engine to extreme power levels can lead to transmission issues. 

Which one should you choose?

• If your priority is hauling heavy loads up steep inclines and you need maximum low-end grunt: The 6.7L Cummins is likely the better option. 
• If your priority is a balance of performance and efficiency for daily driving and you value quicker acceleration: The 6.7L Powerstroke is the better choice. 
• If you plan on heavy towing, consider the transmission behind the engine. The Cummins engine in some Ram models is paired with a 6-speed transmission that can be a limiting factor for towing performance. 
• If you are looking at a used truck: Research the specific model years for known issues and reliability reports for both engines. Some model years of the Cummins may have a less robust transmission compared to what a Powerstroke is paired with in a Ford truck. 

What year of 6.7 Power Stroke to avoid?

The 6.7 Powerstroke years to avoid are primarily 2011-2014 due to issues like turbocharger failures (especially in 2011-2012 models with ceramic bearings), oil pan leaks, and intercooler leaks. While later models are more reliable, the 2017-2019 models can also have problems with the high-pressure fuel pump and oil cooler, and the 2020-2021 models had issues with the 10-speed transmission before an update in 2022.
 
This video explains the common issues in the first generation of the 6.7 Powerstroke: 1mFlying WrenchesYouTube · Jan 29, 2025
2011-2014: The first generation 

• Turbocharger: Early 2011-2012 models are notorious for turbo failure due to ceramic bearings. Leaks from the turbo coolant fittings were also common, with a fix implemented in 2015. 
• Oil Pan: 2011 models had a plastic oil pan that was prone to leaking, requiring transmission removal for replacement. 
• Intercooler: Internal intercooler leaks that push coolant into the engine are more common in this generation. 
• Vacuum Pump: Some early models had issues with vacuum pump bolts backing out. 
• Exhaust Valves: Some very early 2011 models (pre-mid-March build date) had defective exhaust valves that could cause catastrophic engine damage. 

Later generations with issues

• 2017-2019: These models can have issues with the high-pressure fuel pump, leading some to recommend an aftermarket fuel system kit. Problems with the oil cooler and front-end steering components were also reported. 
• 2020-2021: These years had problems with the 10-speed automatic transmission. The 2022 model year saw an updated, more reliable 10-speed transmission. 

Which Ford diesel to stay away from?

Ford diesel engines to avoid include the 6.0L Power Stroke (2003-2007) due to numerous reliability issues, the 6.4L Power Stroke for catastrophic engine failure and emissions system problems, and early versions of the 6.7L Power Stroke (around 2011-2012) which had issues with its original turbochargers. The DV6 engine used in some European Ford models is also considered unreliable. 
This video explains the reliability issues of the 6.0L Power Stroke engine: 1mSUV ZoneYouTube · Nov 18, 2025
Engines to avoid

• 6.0L Power Stroke (2003-2007): This engine is known for being problematic and prone to failure due to issues like the EGR system, head gaskets, and oil cooler. 
• 6.4L Power Stroke: While not as notoriously unreliable as the 6.0L, this engine is also frequently cited for major problems, particularly with its emissions control systems and has been associated with catastrophic engine failures. 
• Early 6.7L Power Stroke (2011-2012): The very first models of the 6.7L had a specific issue with the turbocharger's ceramic bearings which were resolved in later versions. 
• DV6 Engine: This 1.6L diesel engine, developed in partnership with PSA Group, is known for issues like connecting rod failure and seized injectors. 

What to do instead

• If you need a Ford Power Stroke, the 7.3L is known for its longevity, and the 6.7L Power Stroke is generally considered reliable, especially in later model years. 
• If considering an older engine, focus on models from 2006 or 2007 for the 6.0L, as those later production runs seemed to have fewer issues. 

You can watch this video to learn how to identify reliable Ford diesel engines: 44sGetty's GarageYouTube · Mar 10, 2025