Rotella T5 VS T6- Which is Better to Pick

If you think about better performance for your new vehicle then undoubtedly Rotella T6 is best but if you are looking for cost-effective engine oil for your old vehicle then Rotella T5 is also a good option.

There is not much difference between these two oils but the things that separate them somewhat are their viscosity, formulation, and price. The main difference is that T5 is formulated as a synthetic blend or semi-synthetic and T6 is a full synthetic which is a little bit more costly than T5. But at the end of the day, you decide to choose which one is more suitable.

It can be undoubtedly said that both Shell Rotella T5 and T6 are great oils for any vehicle. But if the question is asked which of the two would be the most useful to choose, it can be difficult to answer.

In this article, we will share the differences between the Rotella T5 VS T6 as well as will mention which one should be chosen. So, let’s get started.

Rotella T5 VS T6

Pros and Cons

Both these oils are formulated to meet the needs of modern diesel engines. However, they each have their advantages and disadvantages that should be considered before selecting the right oil for your vehicle.

Rotella T5 Pros:

  • Provides excellent engine protection and performance in all driving conditions
  • Offers reliable protection against wear and tear
  • It contains detergents that help keep engines clean
  • Has a high viscosity index to maintain its viscosity over a wide range of temperatures
  • Compatible with all types of diesel engines
  • Reduced oil consumption
  • Affordable price

Rotella T5 Cons:

  • May not provide the same level of protection as full synthetic oils
  • Some users have reported increased fuel consumption with this oil

Rotella T6 Pros:

  • Wide range of viscosity grades to meet the requirements of most vehicles
  • Excellent oxidation stability to prevent oil breakdown
  • Outstanding shear stability to maintain viscosity under high temperatures
  • Excellent protection against rust, corrosion, and wear
  • Enhanced detergent/dispersant system to keep deposits from forming
  • Compatible with synthetic and conventional oils

Rotella T6 Cons

  • Can be expensive compared to some other brands
  • May require frequent oil changes for some vehicles

A Comparison between Rotella T5 VS T6

When it comes to selecting the right oil for your diesel engine, the Rotella T5 and Rotella T6 are two of the most popular options. While both are formulated for diesel engines, there are some differences between the two. Here are the key points to consider when choosing between Rotella T5 VS T6.

What Is The Difference Between Rotella T5 and T6

Rotella T5 and T6 are both high-quality engine oils produced by Shell, designed primarily for diesel engines, but they have key differences in their formulation and performance characteristics:

Brief T5 vs T6 Rotella Comparison and Overview

Rotella T5: This is a synthetic blend motor oil. It combines conventional base oils with synthetic base oils to offer improved protection and performance over traditional motor oils while being more cost-effective than full synthetics.

Rotella T6: T6 is a full synthetic motor oil. It is made entirely from synthetic base oils, providing superior protection and performance, particularly in extreme temperatures and heavy-duty applications.

Let’s dive deeper!


Viscosity is a measure of an oil’s thickness and its ability to flow. It plays an important role in engine lubrication, as the oil must flow readily to reach all parts of the engine.

Rotella T5 is available in two viscosity grades: 15W-40 and 10W-30. The 15W-40 grade is thicker and provides more protection in high-temperature conditions, while the 10W-30 grade is thinner and provides better flow in low-temperature conditions. Another less popular grade is also available which is Rotella T5 10W-40 CJ-4

Rotella T6 is available in a 5W-40 viscosity grade. This lower viscosity provides improved fuel efficiency and better low-temperature performance compared to the T5 10W-30 grade. Additionally, the lower viscosity of T6 allows for better flow and protection in high-temperature conditions, as well.

It’s important to choose the right viscosity grade for your engine based on the manufacturer’s recommendations and the conditions in which the engine will be operated. The other two grades are also available in T6 SKU that is 0W-40 & 15W-40 which is not too much popular as T6 5W40.


While comparing Rotella T5 VS T6; one of the major things to consider is additives. In this case, they both have a lot in common. Both are formulated with detergents and dispersants to keep your engine clean and running smoothly. They also both contain corrosion inhibitors to fight off rust and other damage.

But the difference is in the level of ZDDP they contain. ZDDP is an extreme pressure agent that helps reduce wear on the engine. T6 has a higher level of ZDDP than T5, which makes it better for vehicles that see a lot of heavy use, like towing or hauling.


Rotella T5 and T6 are both compatible with diesel engines, including those that use diesel fuels that meet the latest emission standards. Both oils also meet industry performance specifications, including API CJ-4, and are suitable for use in a wide range of diesel engines.

In terms of compatibility with engine components, Rotella T5 and T6 are both formulated to protect against wear, deposits, and corrosion.

T5 contains a balanced blend of detergents, dispersants, and corrosion inhibitors to maintain engine cleanliness and control soot buildup, while T6 has a more robust additive package that provides improved wear protection and deposit control.


The performance of both products is very similar. Both are all-season products, rated for a variety of temperatures and applications. They both have good flow characteristics at low temperatures and resist breakdown at higher temperatures, making them suitable for any season.

Where they differ is that the Rotella T6 has an increased tolerance for high temperatures. It also has additional active cleansing agents, detergents, and dispersants that help protect the motor from engine deposits.

It’s better suited to keeping engines clean and running smoothly even in warm weather or high-load conditions. So, if your driving habits tend to put more pressure on your engine, then the T6 might be a better choice.

Oil Change Intervals

Now let’s take a look at the oil change intervals. It’s important to regularly change your engine oil to keep it working properly.

Rotella T5 comes in 4 different formulations, one of which only requires an oil change every 15,000 miles or 12 months, which is very impressive. The other 3 formulations require changes every 7,500 miles or 6 months. However, all formulations need to be changed sooner both in mileage and time if the engine is used for severe service conditions.

On the other hand, Rotella T6 also comes with 4 different formulations, and they all require an oil change every 10,000 miles but have to be changed sooner if used under more severe conditions.

So, when it comes to oil change intervals, it looks like there’s no clear winner since both engines have similar requirements but Rotella T5 can go further in between changes if you use its right formulation.


It’s time to take a look at the prices of Rotella T5 and T6. The price of T6 is between $35-$50 per 5-quart jug. This makes Rotella T6 more expensive than its predecessor, as it tends to be on the high side of that range. In comparison, you can get 5 quarts of Rotella T5 for around $20 -$30.

So, if you have the budget and your engine needs it then you should probably opt for the Rotella T6. If your budget is tight or your vehicle doesn’t necessarily require synthetic oil then the less expensive Rotella T5 is a great option.


Before moving to the head-to-head comparison; we would suggest you check the specifications differences between these two. So, check out their specification differences.

SpecificationsRotella T5Rotella T6
API Service ClassificationCK-4CJ-4
SAE Viscosity Grade10W30,10W40,15W400W40,5W40,15W40
Viscosity, Kinematic (cSt) @ 40°C9572
Viscosity, Kinematic (cSt) @ 100°C14.511
Total Base Number (TBN), mg KOH/g1011
Cold Cranking Simulator (CCS), °C, cP-25°C, 6,000-26°C, 7,000

One thing that you must need to remember is that these specifications are typical for Rotella T5 and T6 and may vary depending on the specific product formulation and batch. We will suggest you check the product data sheet for the most accurate and up-to-date information.

Rotella T5 VS T6- The Winner

When comparing Rotella T5 and T6, there’s no clear-cut winner. It all depends on what your needs are and what you’re looking for in oil. Both T5 and T6 have their advantages and drawbacks, so it’s important to think about your individual needs before making a decision.

If you are looking for better mileage or improved performance, then T5 may be the best choice for you. If you’re looking for more additives or better protection against wear and tear, then T6 might be a better option.

Ultimately, the choice is yours! With both Rotella T5 and Rotella T6 being high-quality oils with different capabilities, it’s hard to go wrong either way.

rotella t5 vs t6

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Can you Mix Rotella T5 and T6?

Mixing different grades of engine oil, like Rotella T5 and T6, is generally not recommended because the two could have different levels of viscosity and additives. Using two different grades of oil may lead to reduced performance, poor lubrication of engine parts, and can even cause engine damage.

It is best to stick with one oil grade to ensure that your engine is properly lubricated. Rotella T5 and T6 are both formulated to meet the needs of heavy-duty diesel engines, however, they may vary in terms of viscosity and additives. Rotella T5 is a 15W-40 grade oil and Rotella T6 is a 5W-40 grade oil.

If you are considering using both Rotella T5 and T6, it is best to consult your owner’s manual or a certified mechanic to make sure that your engine is compatible with the two grades of oil. It is also essential to follow the oil change interval recommended by your engine manufacturer.

Frequently Asked Questions

Q. How long does Rotella T5 last?

Rotella T5 is a synthetic heavy-duty engine oil made by Shell. It is designed to last up to 50,000 miles or over a year.

Q. Is Rotella T5 good oil?

Yes! It would be a great engine oil for on-highway fleets, construction, agriculture, and similar heavy-loaded diesel pick-up trucks or other vehicles where resistance to increased heat and stress is required.

Q. What are the differences between Rotella T4, T5, and T6?

The main difference between the Rotella T4, T5, and T6 is their viscosity.  The lower the viscosity, the easier the oil will flow at lower temperatures and the better it will perform in cold weather conditions. The T6 oil also has a higher level of detergents, dispersants, and anti-wear additives than the other two oils, which helps to reduce engine wear and keep the engine cleaner.

Q. Is Rotella T6 really synthetic?

Shell Rotella T6 5W-40 diesel engine oil is a fully synthetic motor oil that features exclusive Triple Protection Plus technology, formulated with fully synthetic base oils plus advanced additives to protect against wear, deposits, and oil breakdown.

Final Thought

It comes down to the specific needs and preferences of the vehicle owner. Rotella T5 & T6 both have their unique benefits and drawbacks, so it’s important to weigh your options and make a decision that you feel comfortable with.

Hopefully, this small effort will be helpful for all of you. If you have any questions about which of the two is the better choice for you, don’t hesitate to contact us. Thanks for reading!

Read Also: Delo Vs Rotella Vs Delvac


I am Engr. Z Eusuf Lubricant Specialist, Mechanical Engineer & has been working with engine lubricants for a long time and knows what makes them work best. I can help you find the right oil for your needs, and I have tips on how to keep your engine running at its best.