The Most Reliable Mercedes Diesel Engine, Ranked

Voting rules: Choose the engine you think is the most reliable!

Updated on May 5, 2024 06:55

For car enthusiasts and everyday drivers alike, choosing a reliable engine for their vehicle is paramount. Specifically, those who prefer diesel engines for their longevity and fuel efficiency often look towards trusted brands like Mercedes. However, with several models released over the years, identifying the most reliable Mercedes diesel engine can be a challenge. This site offers a dynamic solution by allowing users to vote on and rank Mercedes diesel engines based on their personal experiences and satisfaction. Whether you are in the market for a new car or simply curious about how different engines stack up, your participation helps create a valuable resource that guides decisions and fosters informed discussions.

What Is the Most Reliable Mercedes Diesel Engine?

1

53
votes
OM617

This engine was produced from 1974 to 1985 and is known for its reliability and durability. It was used in the W123 and W126 models and has a reputation for lasting over 500,000 miles.
The OM617 is a renowned diesel engine designed and produced by Mercedes-Benz.

Engine Type: Inline 5-cylinder

Displacement: 3.0 liters

Fuel Type: Diesel

Fuel Injection: Mechanical indirect injection

Aspiration: Naturally aspirated or Turbocharged
2

30
votes
OM642

This engine is a newer design and is used in the current E-Class, S-Class, and GLE-Class models. It has proven to be reliable and has good fuel efficiency.
The OM642 is a V6, 3.0-liter turbocharged diesel engine produced by Mercedes-Benz. It is known for its exceptional reliability, power, and efficiency.

Engine Type: V6

Displacement: 3.0 liters

Fuel Type: Diesel

Turbocharging: Yes

Power Output: Approximately 221-261 horsepower
3

36
votes
OM603

This engine was produced from 1985 to 1999 and was used in the W124 and W126 models. It is known for its durability and long lifespan.
The OM603 is a diesel engine developed by Mercedes-Benz. It belongs to the family of inline-six engines and was produced from 1985 to 1996. Known for its reliability and longevity, the OM603 is often considered one of the most reliable Mercedes diesel engines.

Valvetrain: Single overhead camshaft

Engine Type: Inline-six

Displacement: 2.9L/3.0L/3.5L/3.6L

Fuel System: Diesel direct injection

Compression Ratio: 22.0:1
4

15
votes
OM646

This engine is used in the C-Class and E-Class models and has proven to be reliable over the years. It has good fuel efficiency and low emissions.
The OM646 is a compact and reliable four-cylinder diesel engine developed by Mercedes-Benz.

Displacement: 2.1 liters

Number of cylinders: 4

Valvetrain: DOHC

Fuel system: Common rail direct injection

Turbocharging: Sequential multi-stage turbocharging
5

20
votes
OM611

This engine is used in the A-Class, C-Class, and E-Class models and is known for its reliability and durability. It has good fuel efficiency and low emissions.
The OM611 is a compact and efficient four-cylinder turbocharged diesel engine manufactured by Mercedes-Benz.

Engine Type: Inline 4-Cylinder Diesel

Displacement: 2.2 liters

Power Output: 115-177 horsepower

Torque: 184-330 lb-ft

Fuel Injection: Common Rail Direct Injection
6

7
votes
OM352

This engine was produced from 1964 to 1991 and was used in a variety of vehicles, including trucks and buses. It is known for its durability and long lifespan.
The OM352 is a highly regarded diesel engine developed by Mercedes-Benz. It has been a staple in the automotive industry for several decades, known for its reliability and durability. This engine was widely used in various Mercedes-Benz commercial vehicles, military vehicles, and industrial applications.

Engine Type: Inline 6-cylinder

Displacement: 5.7 liters

Power Output: ranging from 85 to 150 horsepower

Torque Output: ranging from 180 to 280 lb-ft

Fuel Type: Diesel
7

12
votes
OM636

This engine was produced from 1949 to 1985 and was used in a variety of vehicles, including trucks and boats. It is known for its durability and long lifespan.
The OM636 is a four-cylinder, naturally aspirated, diesel engine that was manufactured by Mercedes-Benz. It is known for its reliability and longevity, gaining a reputation as one of the most dependable Mercedes diesel engines in its time.

Engine type: Four-cylinder, naturally aspirated

Displacement: 1.7 liters

Power output: 38-40 horsepower

Torque: 96 Nm (71 lb-ft)

Bore x Stroke: 80 mm x 95 mm
8

7
votes
OM615

This engine was produced from 1968 to 1985 and was used in the W115 and W123 models. It is known for its durability and long lifespan.
The OM615 is a four-cylinder diesel engine developed by Mercedes-Benz.

Engine Type: Inline-4 Diesel

Displacement: 2.2L (2,197 cc)

Power Output: 50-65 hp

Torque: 85-100 lb-ft

Fuel System: Indirect Injection
9

12
votes
OM640

This engine is used in the A-Class and B-Class models and is known for its reliability and fuel efficiency. It has low emissions and meets Euro 5 standards.
The OM640 is a reliable Mercedes diesel engine known for its fuel efficiency and low emissions. It was developed by Mercedes-Benz, a renowned automotive manufacturer. The engine is commonly found in smaller Mercedes vehicles and offers a balance between performance and economy.

Engine Type: Inline-4 Turbocharged Diesel

Displacement: 2.0 liters

Power Output: 136 horsepower

Torque: 300 Nm

Fuel Injection System: Common Rail Direct Injection (CDI)
10

11
votes
OM457

This engine is used in heavy-duty trucks and buses and is known for its durability and reliability. It has low emissions and meets Euro 5 standards.
The OM457 is a highly reliable Mercedes diesel engine known for its performance and durability.

Engine Type: Inline 6-cylinder

Displacement: 11.97 L

Power Output: 310-476 hp

Torque: 1,650-2,000 Nm

Compression Ratio: 17:1

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Discussion

Ranking factors for reliable engine

When determining the reliability of a Mercedes diesel engine, some key factors to consider include

1. Age of the engine: Generally, newer engines tend to be more reliable than older ones due to advancements in technology and engineering.
Maintenance history

Regular maintenance, such as oil changes and filter replacements, is crucial for the longevity and reliability of any engine.
Known issues

Researching common problems and faults associated with specific Mercedes diesel engines can help identify potential issues.
Mileage

Engines with higher mileage may have experienced more wear and tear, potentially impacting their reliability.
Driving conditions

Constant exposure to extreme temperatures, heavy loads and stop/start driving can reduce the engine's lifespan.
Manufacture date

Mercedes has produced many diesel engines throughout the years and some decades yielded more reliable engines than others.

About this ranking

This is a community-based ranking of the most reliable Mercedes diesel engine. We do our best to provide fair voting, but it is not intended to be exhaustive. So if you notice something or engine is missing, feel free to help improve the ranking!

Statistics

4912 views
192 votes
10 ranked items

Voting Rules

A participant may cast an up or down vote for each engine once every 24 hours. The rank of each engine is then calculated from the weighted sum of all up and down votes.

More information on most reliable mercedes diesel engine

When it comes to diesel engines, Mercedes has been a top player in the market for decades. The brand has a reputation for producing reliable and efficient diesel engines that are favored by many car enthusiasts. Mercedes diesel engines have been used in a wide range of vehicles, from luxury sedans to commercial trucks. One of the most reliable Mercedes diesel engines is the OM617. This engine was produced from 1974 to 1985 and was used in the popular Mercedes-Benz 300D sedan. It is known for its durability and longevity, with some engines lasting over 500,000 miles. Another reliable Mercedes diesel engine is the OM606, which was produced from 1993 to 1999. This engine was used in the E300D and S300D models and is known for its smooth performance and low emissions. Overall, Mercedes diesel engines are known for their impressive power and fuel efficiency. They are a popular choice for drivers who prioritize reliability and longevity in their vehicles.