LAST UPDATED: November 21, 2019
Best Oil for 6.7 Cummins: Keep Your Engine Running Smoothly
Keep your engine running at peak efficiency with our picks for the best oil for Cummins engines
The Review Team
How We Decided
The Drive and its partners may earn a commission if you purchase a product through one of our links. Read more.
PUBLISHED ON November 21, 2019
Not all motor oil is made the same. This is especially true for motor oils formulated for diesel engines. Each engine has special requirements that not all motor oils address. Manufacturers perform extensive tests on motor oils to determine the optimum characteristics for their engines so they deliver the best performance. Check out our top picks for the best oil for the 6.7 Cummins engine.
Cummins specifically recommends this Valvoline Premium Blue 15W-40 motor oil for engines operating in temperatures above 0 degrees Fahrenheit.
This oil provides good valve recession protection and has a low ash level. It uses a special formulation called triple dispersant chemistry to improve on industry-standard soot protection requirements. It also excels in deposit protection requirements.
Bottles in cartons may be improperly sealed, leading to leakage. May not provide much difference in protection factors over less-expensive oils.
This oil is formulated to Cummins’ specifications to reduce consumption and engine wear caused by high temperatures.
Formulation fights viscosity breakdown. It is factory tested to ensure that it meets Cummins requirements. Resists oxidation and reduces engine wear.
Only available in 1-quart bottles. This oil is more expensive than other approved oils.
Cummins specifically recommends this motor oil for the Cummins 6.7 engine that operates in temperatures below 0 degrees Fahrenheit.
This motor oil has been extensively tested and proven to extend valve train life as well as low oil consumption and deposit control. Formulated for extremely low temperatures.
The bottles may be improperly sealed, causing leakage during shipment. It’s a bit pricey and may not last as long as some other brands.
Why Trust Us
All of our reviews are based on market research, expert input, or practical experience with most products we include. This way, we offer genuine, accurate guides to help you find the best picks.
Benefits of Oil for 6.7 Cummins
- Less wear. These lubricants have been proven to reduce engine wear. Less wear means longer engine life and improved power, performance, and fuel efficiency.
- Reduced pollution. With improved performance and low ash content, especially in emissions-treatment equipped diesel engines, fewer pollutants escape into the atmosphere.
- OEM-recommended. When you use oil that the manufacturer recommends, you are sure to be following the OEM’s maintenance requirements. This helps keep the vehicle under warranty while promoting peak engine performance.
Types of Oil for 6.7 Cummins
Diesel motors combust fuel at a higher compression ratio than gas motors, at approximately 40,000 to 50,000 psi. Therefore, they require lubrication that can tolerate higher compression ratios. Synthetic oil is formulated to do this. While synthetic oil may be more expensive, it allows your diesel engine to operate more efficiently and with more power than with conventional oils.
You can also use a natural oil that is high viscosity in your Cummins diesel engine. The viscosity is the lubricating ability of oil. Depending on a number of factors including use, the engine size and output, and the ambient conditions, the higher the viscosity, the more lubricating potential an oil has. The numbers of the oil type indicate viscosity: The first number is the lower temperature range of operation and the second number is the higher temperature range. Because of the high compression of diesel motors, they need high viscosity oil, such as 15W-40.
Detergent vs. Non-Detergent
Detergent oils contain additives, mostly magnesium sulfates, that neutralize and clean impurities in oil. These impurities may cause sludge (deposits) on engine components. Non-detergent oils contain no additives to do any cleaning work. Detergent oils tend to maintain their viscosity better in high-temperature conditions and under load.
Valvoline was founded in 1866 by Dr. John Ellis. He was looking beyond the reputed healing properties of crude oil and instead developed a lubricating agent for steam engines that helped eliminate sticky valves and corrosion in cylinders. The Valvoline name was trademarked in 1873. In 1939, Valvoline introduced oil with 18 additives, so there was no longer any need to add them individually to oil. The company developed an all-climate oil in 1954; they subsequently introduced a racing oil, a synthetic blend, and NextGen, which has a reduced impact on the environment and improved miles per gallon. The company’s corporate headquarters today is in Lexington, Kentucky. Try the Premium Blue One Solution 10W-30 Synthetic Blend and European Vehicle SAE Full Synthetic.
As a farm boy, Clessie Lyle Cummins built a steam engine at age 11. He later joined the team that built the car that won the first Indianapolis 500 race. In 1919, Cummins, with financial help from a banker, founded the Cummins Engine Co. in Columbus, Ohio. Together, they wanted to build motors based on technology engineered by Rudolph Diesel. The company remains headquartered in Columbus today. One popular Cummins product is the ONAN SAE 30W oil.
Best Oil for 6.7 Cummins Pricing
- $17-$32. In this category, you can get up to 5 quarts of oil. It can be a full synthetic or synthetic blend. Some of the products come in one-gallon containers, others in 5-quart or 2.5-gallon containers. Viscosity ranges are 5W-20 to 15W-40.
- $33-$78. This category features a similar viscosity as the lower price range but you can get as many as three 1-gallon containers for your money. Only full synthetic oils are found in this price range.
- $79-$149. This range offers 5-gallon pails of synthetic motor oil for your Cummins 6.7 engine. Viscosity ranges are from 5W-40 to 15W-40. This price category includes one oil that is specially blended for Ford under the Motorcraft name.
Obviously, you want the oil you choose to do its main job: lubricate the components of your Cummins 6.7 diesel engine. The OEM recommendations can guide you here, but you may want to read what others are saying about the oil you are considering with regards to its lubricating power. If the oil does not do this main job correctly, efficiently, and for a good price, it’s not the oil for your truck.
You want your oil to protect your engine in extremely cold and extremely hot weather. It can’t thicken too much in the winter or thin out in the summer, or it could inhibit proper starting and operation. Dust and dirt conditions are also a consideration. If you work in dusty, dirty areas, or drive off-road, your oil needs extra detergent power, and your engine will need more frequent oil changes as well.
Many drivers are concerned with how their vehicle affects the environment, especially air pollution. Some diesel oil producers specially formulate some of their products to help reduce soot and nitrous oxide emissions. Others formulate their oil so it works best in the newer emissions-treatment engine designs.
- Price. If one brand of oil for 6.7 Cummins is value-priced and does the same (or better) job of lubricating your engine as a higher-priced brand, why waste your money? Shop and compare. It could very well save you a lot of money, especially over the long run. Also, watch for sale prices and quantity deals.
- Quantity. You have your choice here. You can purchase a 1-quart size, 2.5-gallon size, 1-gallon size, or a 5-gallon bucket. Some of the quart sizes only come in 5- or 6-quart cartons. Similarly, some of the gallon sizes come in 3-gallon cartons. Naturally, you’ll want to determine how much you need but also if you buy in quantity, whether it saves you money.
- Brand Reputation. It’s wise to buy from a brand you know and trust. You don’t want to go with a questionable brand when choosing something as important as the oil that is responsible for keeping your Dodge Ram truck operating as it should for a long time. Well-established national brands have a good reputation for a reason.
Best Oil for 6.7 Cummins Reviews & Recommendations 2020
This high-quality motor oil for 6.7 Cummins engines has “dispersive polymer technology.” Valvoline states that this provides cold start protection and advanced soot control. The oil also protects your engine against valve train wear and it improves filter restriction when soot levels are high. The oil controls deposits on single and two-piece pistons and protects piston rings and liners.
This oil has a high TBN (total base number, a measure of the alkalinity of the additives), which usually means the oil is better able to neutralize contaminants, including acidic debris and the byproducts of combustion. The oil also offers great protection for engines with modern emissions-treatment equipment and when your Ram truck operates in zero degree Fahrenheit temperatures and above.
Some purchasers say the carton they received was not sealed properly and the oil leaked. Also, some users state that the oil does not provide any more protection for their engines than oils that are less expensive.
Cummins formulated this oil specifically for use in its engines. The formula reduces the chances of your 6.7 Cummins engine consuming oil that the high temperatures of diesel motors produce. It also reduces wear that high temperature conditions can cause.
This blend combats viscosity breaking down as it resists oxidation. The factory tests the formula to meet all Cummins specifications. It provides maximum protection for Cummins engines.
If there is a drawback, it’s that you can only purchase the oil in the 1-quart size. It also tends to be a bit more expensive than other approved oils.
Cummins has endorsed this oil exclusively and recommends owners of trucks with 6.7 Cummins engines to use it in their vehicles. It is a synthetic oil that gives you faster and safer starting in cold weather, especially temperatures below zero degrees Fahrenheit. It also has superior thermal properties to address hot weather conditions.
The oil protects against oxidation and gives better fuel economy than standard 5W-40 oils. Valvoline has tested the oil extensively and has proven that it extends valve train life. Testing also shows that motors consume less and that the oil provides deposit control on parts.
Some users of the oil state that it might not last as long as other brands and that it is somewhat pricey. Some purchasers caution that the oil containers may not be sealed properly, so watch out for leaks in the shipping carton.
Shell Rotella T6 is a state-of-the-art, fully synthetic motor oil blend that’s formulated to improve fuel economy up to 1.5 times its usual level. Its “Triple Protection Plus” technology might sound made up, but it’s actually a trustworthy mixture of additives that works to keep your Cummins engine safe from deposits.
What really got Shell Rotella T6 on our list as an honorable mention, though, was its performance in turbocharged engines. If you’re a turbocharger enthusiast who’s afraid that a 5W-40 oil will never hold the viscosity that you need to maintain pressure in a powerful engine, worry no more. This lube outperforms a lot of “zero-weight” manual-recommended oils that we’ve tried.
Beware if you buy: Shell has a nasty habit of failing to fill the bottles all the way. It’s a great quality oil, but you might have to buy two gallons just to ensure you have one. Occasionally, the seals on the bottles have also been known to leak during shipping.
Given the number of times Valvoline has already showed up on this list, you shouldn’t be surprised to see them again. This time, we’re featuring their high mileage solution, which is available in a wide range of sizes and viscosities.
In Cummins engines with over 75,000 miles on the odometer, Valvoline high mileage oil cleans out sludge and prevents new deposits from forming. It includes the extra detergents and protections older engines need to reverse wear. The seal treatment performs especially well—we’ve seen it stop leaks altogether and keep powerful engines running quietly at over 200,000 miles. It also comes at a great price.
What’s the catch? This is a synthetic blend, not fully synthetic or Dexos-certified, so it might not be the right choice for aging GM vehicles. Don’t believe any seller who tells you it’s Dexos. Also, like many motor oils bought online, there’s a risk of the caps leaking.
Mobil 1 is the official oil of NASCAR, but even if you aren’t regularly driving stock cars at 200 miles per hour, you can get great performance using this lubricant. Like many of our favorites, it contains a seal conditioner that can prevent engine leaks, and reverse leaks that have already started.
As a high mileage synthetic oil, its additives are designed to prolong engine life, but it’s also ideal for extended use: You can go 15,000 miles on this before protection and viscosity really begin to break down. It also flows especially well on cold mornings, so if you’ve been suffering from sluggish starts in the winter, this might be the cure.
One thing that makes us less enthusiastic about Mobil 1 is that, despite claiming to be a high mileage oil, it actually loses a bit of power with engines over 75,000 miles. It’s excellent at stopping leaks but doesn’t last a year at that age, and only quiets engine knocking rather than silencing it all together. In our opinion, it’s also overpriced for 5 quarts.
This engine oil is similar to the Shell Rotella T6 we spotlighted above, with a few key differences. While Rotella T6 is completely synthetic, T5 is a synthetic blend that includes some crude products. That’s not a knock against it, though: It’s a low-ash, low-emission motor oil that’s perfectly suited for use in modern engines.
If we had to describe Rotella T5 in one word, it would be “flexible.” We don’t often see oils with the versatility to work in a Cummins 6.7, motorcycle, ATV, lawnmower, and chainsaw. It promises increased fuel economy and wear protection, and delivers on both counts. We especially like how well it maintains pressure in turbocharged engines.
While this is a common problem, we recommend being prepared for this oil to have leaked during shipping. Also, while the price is good, that’s partly dependent on the rebate process, which is overly complicated.
The last entry in our list of favorite engine oils for a Cummins 6.7 is this synthetic blend from Chevron. Delo 400 XLE is formulated to clean out deposits, protect turbocharged engines, and maintain rigorous modern emissions standards. One gallon comes at an economical price, but that’s not all it offers.
Delo 400 XLE performs well as a mixed-fleet oil. Get a case of it, and you can boost the fuel efficiency of gas and diesel engines on cars, trucks, boats, and outdoor equipment. We saw the best results at searing highway temperatures, where other oils break down under the strain. Despite not being explicitly a high mileage oil, it also works well above 200,000 miles.
The only drawbacks of going with this oil is that it’s not a full synthetic, which might not grant the protection recommended by your owners’ manual. The bottle is also poorly designed, with the handle on the same side as the spout, making it a bit hard for people with mobility issues to pour correctly.
- Always check your owner’s manual for the recommended oil for Cummins 6.7 engines. If you don’t go with the recommended oils, make sure the oil you choose meets or exceeds certain American Petroleum Institute (API) and National Institute for Automotive Service Excellence (ASE) standards.
- Oils are carefully formulated to operate in specific temperature ranges. Buy the proper weight for your environment and season. A lower first number is a thinner base oil for extremely cold temperatures.
- Be careful when changing your oil to not over or under fill your Cummins engine. Too much oil in the crankcase/oil pan can create excess pressure, which can push oil past seals and cause damage.
- When changing your oil, it’s is a great time to change the air and fuel filters as well. Clean air and fuel filters will help your engine run more efficiently and cleanly, giving you better mileage.
Q: What weight oil should be used in a 6.7 Cummins engine?
A: Cummins specifically recommends two Valvoline oils for its engines. The 15W-40 oil is for temperatures above 0 degrees Fahrenheit while the 5W-40 is for extremely cold temperatures.
Q: Are synthetic oils better for 6.7 Cummins engines?
A: That’s open for debate. Some manufacturers and engine builders state that synthetics are better, while others prefer blends. What is universal is that the colder the environment, the lighter weight the oil needs to be to reduce wear during cold starts.
Q: Is Valvoline Premium a good motor oil for 6.7 Cummins engines?
A: Valvoline Premium Blue and Premium Blue Extreme motor oils are specifically recommended by the Cummins factory. Cummins has tested these oils extensively and determined they have characteristics that make them ideal for diesel engines.
Our top pick for the Best oil for Cummins 6.7 engines is the Valvoline Premium Blue 15W-40 Heavy Duty Motor Oil, which is specifically called for by the factory for use in temperatures above 0-degree Fahrenheit.
The Cummins Onan SAE 15W-40 Oil, our best value pick, is also formulated to Cummins factory specifications to deliver optimal performance.