Cummins 6.7 -liter is a heavy-duty diesel engine used in pickup trucks like Dodge Ram and Ram 2500, 3500, 4500, and 5500. Therefore, it requires good quality oil to keep the engine clean, protect it and enhance its service life by offering protection of its critical parts.
Best Oil For 6.7 Cummins Engine includes Valvoline Premium Blue 15W40 oil for its engine operating above 0°F and 5W40 for below 0°F. Other compatible engine oils are Rotella T6 15W40 and 5W40, Amsoil heavy duty and Signature series Max duty engine oil, Delo 400 SDE 15W40, Mobil Delvac 1300 Super, and Super Tech heavy duty 15W40 motor oils. Besides the SAE rating, it should also comply with the API CK-4 and CJ-4 specifications to ensure the best performance. You should change the oil on Cummins 6.7 after 15000 miles or 6 months or 500 hours, whichever comes earlier.
We will discuss other related aspects like oil capacity, its impact on fuel economy, and the benefits of synthetic oil over mineral oil.
Recommended specifications for Cummins 6.7 engine oil
Most diesel engines use 15W40 multigrade oil for their lubrication, which works best for a wide range of temperatures.
Cummins recommends 2 engine oils for the 6.7-liter engine according to their operating condition.
First, you should use 15W40 oil if you operate in average to high outside temperature areas.
The 2nd option is to use 5W40 synthetic oil in significantly lower temperatures below 0 degrees Fahrenheit.
Moreover, it is also required to follow the American Petroleum Institute (API) standards for high-speed diesel trucks.
According to recommendations from Cummins, oil should be API CJ-4 compliant regarding its specifications to ensure better performance and emission control.
However, the latest standard CK-4 is applicable for models after 2017 and is also compatible with all previous models.
If the product does not follow the CK-4 requirements, it will pile ash on the diesel filter.
Moreover, you can also use SAE 10W30 API CK-4 compliant oil in the latest models after 2019 for a temperature range above 0oF.
List of the Best oil for Cummins 6.7 engine
Several engine oil options are available for use in Cummins 6.7 from different vendors. You can use any with a specific viscosity rating and API CJ-4 or CK_4 compliant.
It also depends on the temperature range in which you are operating the vehicle.
Cummins Onan 15W40 Oil
Cummins Onan OnaMax SAE 15W40 oil is compatible with the 6.7-liter engine as it fulfills the required criteria.
It reduces its consumption and improves its protection due to wear and tear. It also forms a protective layer around its parts to prevent damage due to its oxidation at high temperatures.
Moreover, it reduces damage due to changes in viscosity at high temperatures. It is designed explicitly for Onan generator diesel engines.
But its temperature range and viscosity rating are suitable for use in heavy-duty pickup trucks. According to online stores, 1 quart can cost around $9-$17.
Valvoline Premium Blue Oil
Company recommends using Valvoline Premium Blue oil for its diesel engine and heavy-duty applications.
It has an SAE viscosity grade of 15W40 and has longer service life for use in Cummins 6.7.
In addition, it has excellent lubrication performance and offers protection from harmful acids that can cause the parts to wear or break down in the long run.
Therefore, using Premium Blue oil will result in a reduction in its maintenance costs and an increase in its useful life.
Valvoline adds many additives to the product to prevent oxidation and an improved viscosity range with temperature changes.
In addition, it removes fine metallic particles and other debris produced during the movement of its parts.
It is also suitable with exhaust gas recirculation (EGR) and selective catalyst reduction (SCR) features available with Cummins 6.7.
Furthermore, it removes harmful pollutants like ash from fuel burning to prevent their deposition on its parts.
It also performs well in colder environments, preventing it from becoming too thick.
However, you should avoid its use with diesel trucks with diesel particulate filters. You can buy its gallon for $19-$21.
Shell Rotella T6 15W40
Shell Rotella T6 15W40 full synthetic engine oil is one of the best for heavy-duty diesel engines.
It has all the features of a suitable lubricant, including wear protection, anti-oxidant properties, improved viscosity control at low temperatures, and maintaining its cleanliness to prevent abrasion.
Furthermore, it has an additional feature of maintaining its flow at lower temperatures up to 5oF.
Therefore, you can use it in such cold climate conditions without putting extra stress and minimizing wear and tear.
Most drivers prefer this product because of its performance beyond the API CK-4 requirements in coping with corrosion, wear, and tear, and frictional losses between the parts.
Moreover, it has lower volatility owing to its additives, including detergents and dispersants, which can also help reduce its consumption.
Furthermore, it has triple protection plus technology to ensure its long life, reduced wear and tear, and lesser particulate deposits.
Shell Rotella T6 5W40 is also available for use in cold temperatures below 0 degrees Fahrenheit.
It has all the properties of T6 15W40 oil, but it has flowability even at temperatures as low as -29oF. It costs around $24-$25 per gallon.
Shell Rotella T4 15W40
Shell Rotella T4 15W40 is an inexpensive alternative for T6 oil, having most of its features.
Moreover, it protects critical parts like valve trains, piston rings, and cylinder liners. It complies with federal emission control regulations and has durability for extended service life.
It also has triple protection technology to reduce its wear, breakdown, and deposits on its parts.
In addition, it has excellent lubrication properties, longer life, and a wide temperature range, fulfilling the requirements of several climate conditions. It will cost you $36-$37 for its 2.5-gallon pack.
Amsoil Heavy-Duty Synthetic Diesel Oil
Amsoil heavy-duty synthetic diesel oil is available in both SAE 15W40 and 5W40 viscosity ratings. You can select the one for your Cummins 6.7 according to operating conditions.
According to third-party testing, it has 3-4 times better wear protection than conventional oils.
Their other features are optimal performance in lower and higher temperature extremes and reduces damage to ensure minimum maintenance costs and downtime.
It also performs better regarding its consumption required in the CK-4 standard. It has more than 60% less usage than the standard limit.
It maintains its viscosity despite oxidation and mixing of soot with the oil. You will also observe a slight increase in fuel economy using Amsoil heavy-duty synthetic diesel oil. It will cost you $10-$11 per quart bottle.
Amsoil Signature Series Max Duty Synthetic diesel oil 15W40 and 5W40 is also compatible.
In addition, it has even better specifications than heavy-duty diesel oil, including 5-6 times better wear protection, corrosion protection, and more than 70% less consumption.
Therefore, you can use it for high-performance applications by paying more for its price. It will cost you $14-$15 per quart.
Delo 400 SDE 15W40
It is an API CK-4 compliant engine oil with SAE 15W40 viscosity rating.
It has ISOSYN advanced technology that gives it features like durability, wear resistance, and protection of its parts by adding chemicals.
It also ensures the cleanliness of the machine to minimize its downtime and maintenance costs. In addition, it has superior features like low carbon emissions due to improvement in the fuel economy.
It is compatible with the latest features like EGR, SCR, and diesel particulate filter (DPF) available in Cummins 6.7 to control emissions and fulfill EPA requirements. You can buy its 1-gallon pack for $16-$17.
Mobil Delvac 1300 Super 15W40 Oil
Mobil Delvac 1300 Super 15W40 is a mixed synthetic oil that fulfills all the requirements of a lubricant mentioned in the API CK-4 standard.
It will also provide protection against wear and is durable enough to last for 1.5 times OEM recommended oil change intervals.
It has standard lubricant features like viscosity control for a wide range of operating temperatures, soot control, less consumption, and anti-oxidant properties to prevent corrosion.
It is not fully synthetic, and you can expect lower prices yet standard features. It has a price range of $30-$32 for a 2.5-gallon pack.
Super Tech Heavy Duty 15W40 Motor Oil
Super Tech Heavy Duty engine oil has an SAE rating of 15W40 and also complies with the requirements of API CK-4 and all previous standards.
It has features of a lubricant like an engine protection and its enhanced performance.
It performs well under different operating conditions and a range of temperatures without being too thick to be pumpable.
Although it is a low price product, it has excellent customer reviews because of its standard features. You can buy it for $4-$5 per quart.
Mobil 1 Turbo Diesel Truck Oil 5W40
Mobil 1 turbo diesel truck oil has an SAE rating of 5W40 and companies with API CK-4 and CJ-4 specifications.
It is among the best options for Cummins 6.7-liter engine for use in extremely low temperatures to ensure its startup.
You can change it beyond manufacturer-recommended intervals without much deterioration and effect on its lubrication properties.
It will improve the fuel economy under different operating conditions like temperature, driving style, and viscosity.
Furthermore, it prevents the parts from oxidation at high temperatures and the sludge buildup at low temperatures choking its movement. You can buy it for $35-$37 per gallon.
Motul 8100 X-Cess 5W40
It is a fully synthetic diesel engine oil and can use it in extremely colder operating conditions as it has an SAE rating of 5W40.
Its 5-liter pack can cost $44-$45. It has other lubricant features, including reduced wear, anti-oxidant properties, and parts like cylinders, piston rings, and overhead valve trains.
Although the manufacturer recommends it for cars, it has specifications compatible for use in outside temperatures below 0 degrees Fahrenheit.
Recommended oil filters for 6.7 Cummins Engine
The oil filter is one imperative component that you have to change during every oil change operation.
It should be of good quality to ensure its cleaning to prevent residual metallic particles and sludge from re-entering the engine.
Mopar is one of the best filters recommended by expert mechanics and has good customer reviews.
Other filters having good quality for use with a diesel engine are Fleetguard, Baldwin, and Wix brands.
How often should you change the oil in a 6.7 Cummins?
According to manufacturer requirements, you should change Cummins 6.7 engine oil and filter after 6500-7500 miles, or 6 months for 2007-2012 models.
For 2013-onwards, you should change it after 14000-15000 miles or 6 months or 500 hours.
However, the manufacturer recommends these limits under ideal operating conditions and are valid for synthetic oils.
But I suggest you change it at the right time by observing the oil condition, level, pressure, and operating conditions.
Moreover, these limits are much lower for conventional products. Therefore, you should be careful in this aspect to enhance the vehicle’s life.
How much oil does a 6.7 Cummins Engine take?
Cummins 6.7 is a 6-cylinder engine available in heavy-duty pickup trucks like Ram 2500 and 3500 with or without turbochargers.
It has a capacity of 10.5-12 quarts of engine oil for the latest models.
If you change its filter, then you have to refill it while installing to prevent the air from trapping.
Therefore, it will take 12 quarts. While without a filter, it will take 10.5-11 quarts.
You should regularly check its level and refill the required amount if it is low.
Why does Cummins recommend synthetic oil for the 6.7 diesel engine?
Cummins recommends using synthetic oil instead of conventional mineral oil for its 6.7-liter engine.
It is chemically modified to make it refine and improve its chemical properties.
Therefore, it has desirable properties like stable viscosity, less degradation with increased temperature, improved fuel economy, and better protection.
Moreover, it is more durable than conventional oil and lasts longer. In comparison, you need to frequently change the mineral oil due to the smaller drain interval.
Does using recommended oil improve the fuel economy of the Cummins 6.7 engine?
All good quality synthetic engine oils have an impact on their performance.
Therefore, they will also slightly improve the fuel economy or maintain it up to EPA ratings.
However, if you don’t change it at recommended intervals, it will drastically reduce the fuel economy.
Therefore, you should consider it as an essential factor affecting the fuel economy of heavy-duty diesel trucks.
For example, Shell Rotella T6 improves fuel economy by up to 1.5%, but actual figures can vary according to operating conditions.
Improved fuel economy will result in a low amount of fuel burned and hence lower emissions.