Motors come in all shapes and sizes, and as such, you cannot expect a one-size-fits-all engine oil either. Take, for instance, the incredible Cummins 6.7L Turbo Diesel engine found in RAM trucks. For over 30 years, Cummins engines have been found in Dodge RAM trucks, proving that quality engines can stand the test of time. If you want your Cummins 6.7L engine to keep running, you need to make sure you are using the correct oil. Check out the lineup of the best oil for Cummins 6.7 liter engine below!

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The Best Oil For Cummins 6.7 L Engine

Whether you have a 2500 or a 3500 Dodge RAM, you are going to need an oil that keeps your engine working optimally. Of course, finding the best oil for a 6.7 Cummins is more than getting better gas mileage. You want to keep the engine clean and healthy. Here is a list of the best motor oil on the market for your Cummins 6.7L:

Prices pulled from the Amazon Product Advertising API on:

Best of the Best Oil: Shell Rotella T6 Full Synthetic Diesel Engine Oil

The best oil you can purchase for a Cummins 6.7 engine is this: Shell Rotella T6 Full Synthetic Diesel engine oil, crafted for extreme temperatures. With a fully synthetic base and advanced additive composition, you get complete protection from deposits, oil breakdown, and sludge buildup. Furthermore, Shell Rotella T6 Full Synthetic has been proven to increase fuel economy performance and it flows better at lower temperatures.

Think the “Triple Protection Plus” technology claim is bunk? It’s not. The composition of the additives does exactly as promised. The low-ashed formula prevents blockages and improves efficiency in diesel engines. There is also less viscosity lost through shearing.

If you live somewhere with extreme weather patterns, then this is no doubt the best oil for Cummins 6.7L engines around. Shell Rotella T6 is formulated for SAE 5W-40 and 15W-40, but you could also potentially use Shell Rotella T4 to get a 10W-30 formula.


  • Protects your engine through a wide range of temperatures
  • Improves fuel economy
  • Compatible with exhaust emission control systems
  • Fully synthetic motor oil


  • The great quality comes are a cost

Runner Up Oil for Cummins 6.7: Valvoline Advanced Full Synthetic SAE 5W-30

Looking for engine oil that will keep your Cummins 6.7 running for many years to come? Valvoline’s Advanced Full Synthetic Engine Oil is so good that it ties with our other top-tier pick, Shell Rotella T6. The Valvoline formulation does what it promises. Your engine will keep your engine sparkling clean and it meets all the manufacturer requirements. Additionally, Valvoline Advanced Full Synthetic SAE engine oil has a high TBN and retains that value, meaning your oil lasts longer.

This oil also comes with dispersive polymer technology (DPT), meaning that it cleans soot and sludge from the engine and protects the components too. You will notice far less valve train wear when using this motor oil. As a high-performance synthetic, you also get enhanced performance in all kinds of weather.


  • A recommended oil by Cummins, Inc.
  • Improved fuel economy
  • Reduces wear, friction, and sludge deposits
  • Oxidation resistance throughout the engine


  • There really aren’t any

Best Oil for High Mileage Cummins 6.7: Mobil 1 High Mileage Full Synthetic Motor Oil 5W-30

Want your Cummins 6.7 engine to continuously meet your demand, even after it has reached more than 75,000 miles? Then you are going to need a protective engine oil like Mobil 1 High Mileage Full Synthetic Motor Oil 5W-30 protective oil. This oil has been formulated to prevent wear and tear in the engine. As Cummins engines creep up in mileage, they start to guzzle oil, and so you may find that you’re doing more top-ups than before. This oil fixes that need.

Mobil 1 High Mileage Full Synthetic Motor Oil 5W-30 addresses the damages that could have already occurred and washes the engine in conditioning additives to put a stop to such leaks. Your seals will last longer, thanks to these additives, as well as the reduced amount of friction. Furthermore, the Technical Particles Technology works to counteract sludge deposits in the engine.


  • Specifically formulated to protect higher mileage engines
  • Prevents rust, sludge, and corrosion throughout the engine
  • Extends engine life


  • Packaging is poor – no grip and the spout is too wide
  • Funnel use to prevent oil spills

Best Budget Oil for a Cummins 6.7: Pennzoil High Mileage Synthetic Blend 5W-30 Motor Oil

Replacing the oil and doing routine maintenance on your Dodge RAM is, undeniably, a money sink. The cost of owning a vehicle is high, so it makes sense that you want to balance the quality of your truck’s motor oil with a reasonable price. Well, look no further than Pennzoil High Mileage Synthetic Blend 5W-30 oil. To begin, this oil is universally compatible, so you can use it to top off any existing oil without any bizarre or damaging reactions.

Plus, you know it is going to do wonders for your Cummins 6.7 engine, you get enhanced fuel economy and decreased oil consumption. Furthermore, this motor oil is formulated to remain smooth in both warm and hot temperatures, which is when viscosity tends to increase. If you plan on driving for long distances in the summer, consider this engine oil.

Pennzoil High Mileage Synthetic Blend engine oil is also formulated with additives that enhance lubrication. Oxidation is also tackled. In short, if you want high-quality motor oil on a budget, this is a worthwhile selection.


  • Budget-friendly price
  • Works great in warmer temperatures
  • Universal compatibility
  • Protects engine during startup
  • Improved viscosity actions


  • N/A

Best Oil For Cold Temperatures: Mobil 1 Turbo Diesel Truck Oil

Plan on plowing then hauling away snow with your Dodge RAM 2500 or 3500? You’re going to be putting your Cummins 6.7L engine to work. Make sure you have the best cold weather oil for 6.7 Cummins to bolster engine performance. Mobil 1 Turbo Diesel 5W-40 Truck Oil is the best for this purpose.

Against other cold-weather competitors, Mobil 1 Turbo Diesel stands out for its unique additives that protect your engine from damage. Furthermore, the full synthetic oil was formulated for high horsepower engines like a 6.7 Cummins. Fuel economy and oil efficiency are improved.

You can also enjoy full compatibility with other types of oil on the market. However, this oil is best when used with more modern engines, particularly those that have been equipped with Exhaust Gas Recirculation to limit carbon emissions. Since eco-friendly functions tend to increase the heat in your engine, this oil works to shear off some of the temperatures and keep your engine running smoothly.


  • Excellent performance in colder climates
  • Additives help protect the engine from damage and oxidation
  • Works with modern eco-friendly vehicles
  • Improves fuel economy


  • Recommended formula is best for winter or cold climates

Different Types of Oil For Cummins 6.7

Let’s take a quick look at the engine oil types that you should consider for a Cummins 6.7 engine.

Synthetic Oil

The turbo diesel 6.7 Cummins is one of the most impressive systems of 2021 and has a compression ratio of 16:2:1. In other words, combustion within the engine is done under high pressure and heat. For this kind of system, you are going to want a motor oil that is specifically designed for high internal heat. Full synthetic oils are the best for these situations because they are formulated to handle such a strain.

You can find synthetic oils in a variety of viscosities and with various additives and treatments included. Thus, if there is an oil in the list above that you are interested in but want a different viscosity rating, you should be able to find it.

In conclusion, choose synthetic oil if your Dodge RAM is under consistent strain.

High-Mileage Engine Oil

As a sub-type of synthetic oil, high-mileage engine oil is formulated to meet the needs of engines with an odometer of over 75,000. Although you can get around 300,000 miles out of a well-maintained engine, it is crucial that you switch to a high-mileage motor oil before you’re halfway there. High-mileage motor oils are similar to your standard oils, but they include far more additives to prevent oxidation. For example, conditioning agents are added to keep seals softer for longer.

High-Viscosity Motor Oil

You will notice a variety of viscosity ratings on the best oils for Cummins 6.7 L engines. Why? Because different viscosities assist with different things. If an oil is too thin, you won’t get effective performance. If the oil is thicker than necessary, it will not move throughout the engine fast enough.

So when would you get a high viscosity motor oil for your Cummins 6.7? When you need an oil that spreads more quickly, coating the engine and protecting it better.

Conventional Oil

The traditional approach to lubricating your engine. Conventional oil dates back to the time when Castrol used castor oil as an ingredient. These days, conventional oil is far less common. You may still find it in synthetic blends. However, conventional oil does not protect hard-working engines like a Cummins 6.7 well enough. Therefore, when given the option, choose a full synthetic oil instead.

Buying Guide to Choose The Best Oil For Cummins 6.7

Before purchasing motor oil for your pickup truck, make sure you are using the right kind. Take a peek at the owner’s manual to see the recommended engine oil. The manufacturer always prints the information for you to see. After that, there are some things you need to keep in mind when shopping around.


When shopping for appropriate motor oil, the viscosity should play a key role in your selection. Note that the recommended viscosity for a Cummins 6.7 is either 5W-30 or 5W-40. Thus, for the best performance in most scenarios, you are going to want to purchase the recommended viscosity. In the event that your pickup truck is being used for long drives or hauling equipment or is exposed to extreme temperatures, you might want to bump the thickness up to around 10W-30 or even 15W-40 to protect the engine better.


Why are additives important? Without them, your engine oil gives you less bang for your buck. Being that Cummins 6.7L engines are designed for diesel fuel, you are going to want additives that boost the lubricating power of the oil. Anti-wear and corrosion prevention additives are also very important.

Keep in mind that different manufacturers come up with different additive formulas. Some do not play well together, such as Pennzoil and Valvoline, so you should do your research on the additives before mixing two different brands. Consider the specific needs of your engine, so you can find motor oil that supports the way you drive and use your pickup truck.

Most importantly, you want additives that keep your engine clean, so you get better fuel economy and less oil consumption.

Brand Reputation

You may be tempted to buy an off-brand oil to save some money, but that is not advisable. There are some brands in the automotive world that have better reputations than others. Listen to those reputations. Buying products from a trusted brand, such as Quaker State, Pennzoil, Shell, or Valvoline ensures that you are getting a quality product. If you spot a brand that you know nothing about, make sure to do some research to see if their formula has been tested and reviewed.

The problem with buying from brands you know nothing about is that their oil may not be the highest quality. That could cause problems for you and your 6.7 Cummins down the line.

Final Thoughts on Engine Oil for Cummins 6.7

Hopefully, you now have an idea about which is the best oil for Cummins 6.7L engines. Arm yourself with this valuable knowledge so that you can select a brand of oil that is high quality. The right oil is going to have a full spectrum of additives and promote a healthier engine. Choose wisely! If you are looking for the best, go with Shell Rotella T6 Full Synthetic Diesel engine oil, which comes in a couple of viscosities. Which one are you going to choose?

Categories: Oil Guides


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