Top 7 Best Oil for 6.7 Cummins 2023

If you own a Dodge Ram with a 6.7 Cummins engine, then you will have to agree with me that your baby truck has tons of torque, lots of horsepowers and great towing capacity.

Just like every vehicle on the road, regardless of how powerful the engine is, without regularly scheduled maintenance and services, the engine will not provide optimum performance, not to mention when you use the wrong oil type.

If your baby truck is equipped with Cummins 6.7 engine, the right motor oil will make the key difference.

That said, if you want the best from your baby truck, you need to use one of the best oil for Cummins 6.7. Finding the best oil might be mind-boggling, but not to worry, we have outlined the best oils below.

Best Oil for 6.7 Cummins Reviews 2023

The comparison table should represent a peek at what those oils do, but that’s just an insight. There are a whole lot of things to consider prior to purchase.

Read through our comprehensive list of the best oil for Cummins 6.7 engines.

1. Shell Rotella T6 Full Synthetic Diesel Engine Oil

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Shell Synthetic Diesel Oil is a fully synthetic engine oil manufactured with triple protection plus technology. It features an advanced additive with fully synthetic base oil to fight against deposits, buildups, wear, and oil breakdown.

It also has increased fuel economy performance flow by 1%, and better low temperature, and lasts longer than its counterpart – Shell Rotella SAE 5w-40 Conventional Motor Oil. Shell Rotella full synthetic is arguably one versatile motor oil that meets demand.

It is highly recommended for most SAE 5w-40 diesel engines.  Its advanced additive and high-end protection measures make it a good purchase, and it outperforms several choices out there. 


Outstanding shear stability and emission system compatibility

It features an advanced low-ashed formulation that helps in poisoning or blocking exhaust after-treatment devices which helps in maintaining diesel engine efficiency and emission compliance. Shell Rotella T6 diesel oil offers optimal pressure and presents viscosity loss through shear. 

Improved wear protection and better fuel economy

Shell Rotella T6 provides a fuel economy capacity of 1.5% to save you money from gas without compromising quality, durability, and engine protection compared to 15w-40 engine oil in the market. It offers a high level of protection against catastrophic engine wear, helping to extend engine life.

Improved heat resistance and deposit control

Its synthetic base oil and multi-functional addictive offer an advanced level of protection against any effect of grime, dirt, soot or any other contaminants in the engine. It resists breakdown by extreme temperatures to offer consistent protection.


  • Protective in a range of temperatures
  • Compatible with exhaust emission control system
  • Improved fuel economy
  • Fully synthetic-based formula
  • Great mileage improvement 
  • Superior versatility in action
  • Incredible powerful additive


  • Poor packaging quality.

2. Valvoline Premium Blue SAE Engine Oil

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If you’re looking for the best engine oil to keep your engine running for a long, this is the most suitable choice. Valvoline Premium Blue SAE Motor Oil is the right fluid for Cummins 6.7 engines and promotes overall performance and keeps the internal engine components clean. It meets all essential test requirements. Its modern technical formalities offer maximum all-around courtesies.


Excellent TBN value retention

It has a high Total Base Number (TBN) capable of neutralizing any form of contaminants. The TBN composition retains its efficiency even after long hours of use.

Advanced Lubrication Technique

Its modern formalities offer peak performance from the inside out. It passed several examinations conducted by Cummins on several applications, making it a good purchase for Cummins 6.7 engines. It also provides efficiency to diesel engines with emission systems (PDF, EGR & others).

Maximum internal protection

It features dispersive polymer technology (DPT), which makes it a great advanced soot control. It also helps prevent valve train wear. It renders internal optimum protection to the engine system.


  • Advanced cleanliness for engines
  • It Reduces friction, wears, and deposits
  • Betterment in fuel efficiency
  • Incredibly protection performance
  • Outstanding Oxidation resistance


  • Slight oil leak from the cover

3. Delo 400 XLE SAE Synblend Synthetic Blend Oil 15w-40

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Delo Synthetic blend offers superior output enhancement. Delo provides one functional best oil for Cummins diesel engines. It also offers excellent control over deposits and assists engine workability. Delo extends engine lifespan against poor service, and of course, you wouldn’t want to compromise durability by offering poor service maintenance to your engine.


Great chemical compositions

Delo Synblend Synthetic Oil features isosyn technology for advanced functionalities. The isosyn promises high durability to engine components. It also passes OEM cleanliness to keep your engine clean.

Functional blend performance

There are key differences between fully synthetic and synthetic blend oils. But Delo closes the gap via a unique formation. The blended oil incorporates every component in a fully synthetic fluid.

Optimal protection measures

Delo Synblend synthetic oil offers a powerful solvent and additional additive, and It protects the turbocharger.  It also promises minimal downtime resulting in low maintenance engine cost.


  • Improvised cold flow properties
  • It reduces operational cost
  • Perfect for modern engines
  • Patented advanced technology


  • It has a cheap container material

4. Shell Rotella T6 Full Synthetic 15w-40

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Shell Rotella T6 15w-40 full synthetic formulated and designed to offer unbeatable performance compared to blend synthetic and conventional shell Rotella 15w-40 fluids. It is perfect for all 15w-40 light truck diesel engines.

It has passed several automakers’ specification tests that make it a great choice for light trucks and constructions, public transport operators, agriculture, and all diesel trucks that use 15w-40 oil grade.


Cold climate protection

Shell Rotella T6 15w-40 offers low-temperature pump ability at 15 degrees and great cold cranking properties compared to blending synthetic and conventional diesel oil of other Rotella 15w-40 fluid. That implies it lubricates internal engine components faster in cold temperatures to reduce wear in cold or extreme temperatures.

Advanced wear protection

There are basically two common types of wear in an engine; corrosive and mechanical wear. Both kinds of wear occur when acid forms during combustion. The common functionality of engine oil is to reduce or prevent wear.

In the American petroleum institute (API), Shell Rotella T6 15w-40 goes beyond the CK-4 specifications. It showed an incredible 85% improvement in corrosion protection, a wowing 98% improvement in copper corrosion, and an external 50% improvement in wear protection.

Reduces oil consumption

It offers low volatility in addition to dispersal and solvent that reduces oil consumption. Lower volatility = lower oil consumption.


  • Maintains oil pressure and resists viscosity loss
  • Excellent corrosion control
  • Improved wear protection
  • Enhanced deposit control
  • Increased protection against oxidation.


  • Issues regarding oil leak from the cap.

5. Valvoline Blue Extreme SAE 5w-40 Full Synthetic Oil

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Valvoline blue extreme SAE 5w-40 full synthetic diesel oil isn’t just another pick for Cummins 6.7 engine; rather, it is Cummins’s official recommended oil to be used on any diesel engine above 0 degrees Fahrenheit.

This means Valvoline Blue Extreme SAE 5w-40 maintains excellent viscosity in cold temperatures and gives optimal code start performance. It also delivers peak performance in both cold and warm temperatures. In other words, it works well in virtually all temperatures.

The exceptional key component of this oil is that it provides fuel economy above many 15w- 40 oil grades. Some of its key benefits are advanced soot control, enhanced fuel economy, extended service, TBN retention, and excellent all-weather performance.


  • Enhanced fuel economy over conventional oil

It offers a faster and safe start during extremely cold temperatures and allows adequate oil flow throughout the engine components.

Excellent oxidization

Valvoline blue extreme SAE 5w-40 synthetic engine oil incorporates dispersive polymer technology (DPT) for soot control in EGR-equipped engines. It is specifically examined and recommended by Cummins Inc.

Exceptional TBN retention

It features a high (TBN) Total Base Number to neutralize any contaminants in the engine system. The TBN even retains its processing efficiency for a long time.


  • Perfect for both high and low temperatures
  • Great cold start performance
  • Excellent all-weather performance
  • Official Cummins recommended oil for engines operating over 0 degrees Fahrenheit


  • Cover sealing and delivery issues

6. Cummins Onan Engine Oil

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This is one of the best oils for Cummins engines. Cummins produced this oil to specially meet the needs of 15w-40 oil requirements. Cummins Onan Oil is the best oil for Dodge Cummins 6.7. it delivers all requirements. This factory-produced and tested oil has an advanced additive that helps keep your engine very clean. And also, it is compatible with both gasoline and diesel engines.


  • Active engine cleaning performance

Cummins Onan oil features a powerful additive and solvent that offers maximum protection. It fights against any engine buildups or deposits, thereby keeping the entire engine components clean.

Active composition viscosity

Cummins Onan meets 15w-40 viscosity ratings. It prevents oxidation at high temperatures, and its increased viscosity endues fuel economy.

Highly effective formulation

Onan offers an advanced formulation that supports engine overall performance.


  • Good fuel economy
  • Reduces internal engine wear
  • Improved viscosity actions
  • Excellent engine startup


  • High fuel price

7. Mobil 1 122094 5w-40 Formula M

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Mobil 1 122094 5w-40 formula M is another pick you should consider. Mercedes highly recommends this oil for Mercedes cars. As a result of its high demand by most Mercedes users, it is hard to find. That should tell the quality of this fluid. However, just because Mercedes highly recommend it does not make it best for Cummins 6.7 engines. 

In any case, it doesn’t have some extra qualities like most oils on the list, but it is perfect for cold weather – guaranteeing a quick cold start and extending engine life. No engine is good for the environment, but Mobil 1 formula M is a great choice if you’re environmentally conscious. Mobil 1 122094 formula M lasts longer compared to oil in the market segment without compromising the quality or losing viscosity or heat degradation.


Active cleaning agents

Mobil 1 122094 features advanced additives for maximized protection. It fights against heated deposits and unwanted buildups. Therefore, it keeps all internal engine components clean.

Good mileage enhancement

It has high resistance to cold temperatures and offers optimum protection to the engine components. It keeps the whole engine components away from frictional wear, soot, buildups and deposits.


  • Premium additive
  • Highly extended applicability
  • Perfect for cold climate 
  • Advanced cleaning solvent
  • Fewer hydrocarbon pollutants than similar oils


  • Poor packaging quality

Bottom line

The right engine oil makes the key difference in a 6.7 Cummins. Scroll up to the recommended oils above, peruse through the features, pros, and cons – compare them and make the right choice.

Nonetheless, you should bear in mind that all the oils on our list are go-get.

The best engine oil for Cummins 6.7 will extend your engine lifespan and provide peak performance.

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