Delo 15w40 VS Rotella 15w40: Which Brand is the Best?
When you look for heavy-duty engine oil, you must get through some suggestions from your mechanic or vehicle manual guidelines. Maybe Shell Rotella comes to your mind, although Delo and other companies are there with high-quality engine oils. From my garage working experience, I can explain the biggest differences between different engine oils.
It’s not tough for anyone who regularly works with the vehicle and engine oil. However, the Delo & Shell Rotella are the two most famous brands that produce different engine oil, gear oil, and transmission fluids. Let’s see the difference between Delo 15w40 vs. Rotella 15w40 engine oils.
Which Brand is the best between Shell Rotella & Delo?
You cannot easily declare a particular brand best until you use their products and compare them side-by-side. Using both companies’ products and comparing the drawbacks and benefits of those engine oils will be an excellent idea. I did the same thing with these products and used them in the exact vehicle.
They both have their usages, and you can use them under different conditions for superior performance. One is better for winter use; the other is suitable for hot weather. Let’s disclose these engine oils and get a basic idea.
The Delo is a regular engine oil brand that produces high-quality motor oils and transmission fluids that you can use under any condition. The Delo 15w40 is a purely synthetic motor oil with high-quality additives to give you the best protection against wear & tear. However, the Delo 15w40 or other engine oils are better suited for cold weather since they have less viscosity.
Suppose you consider the Shell Rotella engine oils. In that case, you must consider the weather because it will give you the best performance under hot weather since the thickness of 15w40 Rotella motor oil is higher than Delo motor oil. Besides, the Rotella 15w40 is also a pure synthetic blend-based engine oil with premium-quality additives to give you better protection against wear & corrosion.
Here, you can say that these two engine oils or brands better depend on various conditions. If you consider the hot weather, you must go for the Shell Rotella brand. Otherwise, the Delo brand engine oils are better for cold weather. But you cannot say the first brand is better than the second brand before you go through the comparison part.

Let’s Compare Shell Rotella 15W40 with Delo 15W40
- Features: Triple Protection Plus Technology is being incorporated into the Rotella 15w40 to provide improved wear protection and oxidation stability levels. It offers diesel engines the highest level of protection even when operating in high-temperature situations. It is suitable for heavy-duty vehicles of any age, including bus fleets, utility vehicles, and delivery vehicles.
The Delo 15w40 utilizes ISOSYN Advanced Technology, which is designed to provide the highest possible level of engine cleaning and protection. Because of its extended drain intervals, it offers a good economy on fuel. As a result of the quick lubrication that it offers to the engine, it also functions remarkably well in environments with extremely low temperatures.
- Viscosity: The viscosity index may be conceptualized as the rate at which the kinematic viscosity shifts in response to changes in temperature. Due to the fact that Delo has a lower index value than Rotella 15w40, it is more likely to be adversely affected by any changes in temperature.
- Pouring Point: The pour point of engine oil is the final criterion to investigate when comparing viscosity. The temperature at which a lubricant begins to lose its ability to flow freely below which it can no longer be considered a lubricant. Since the relative value of the pour point for Delo is smaller than that of Rotella 15w40, it will lose its ability to flow later than Rotella 15w40.
- Kinematic Viscosity: The kinematic viscosity of Delo is higher than that of Rotella 15w40 when the temperature is low, but when the temperature is higher, it is lower.
- Oil Combustion Protection: When there is a condition of leakage in piston rings or a seal break, engine oil seeps inside the combustion chamber and burns out. Other times, there is no such condition. It leads to the production of toxic ash, which has a detrimental effect on the operation of the catalytic converter.
The proportion of zinc to phosphorous found in lubricants is directly proportional to the amount of ash produced by the reaction. The amount of phosphorus and zinc found in Rotella 15w40 is significantly higher than in Delo. As a result, if you care about the condition of the catalytic converter, you should go with Delo as your option of choice.
The temperature at which the vapor of a lubricant will spontaneously ignite when exposed to an ignition source is referred to as the flashpoint of the lubricant. Because Delo’s flashpoint is far lower than that of Rotella 15w40, it has a higher rate of spontaneous combustion. Because of this, using Rotella 15w40 as your engine’s fuel of choice when the temperature is high is a smart idea.
Oil Changing Frequency: To neutralize the acidic effects of the engine oils, alkaline-derived additives are mixed in. These additives act as a counterweight to the acids, and their neutralization capacity can be measured using a parameter known as the TBN (Total Base Number).
Once the fundamental additives in the engine oil lose their ability to neutralize, it will need to be drained because it will no longer be effective. Because of this, the TBN of engine oil can be used to determine how often the oil should be changed.
The TBN content of Delo is greater than that of Rotella 15w40. It indicates that the process of draining would take place over a longer length of time. As a result, the oil change frequency at Delo is significantly less frequent than at Rotella 15w40.
Who Wins Between Delo 15w40 & Rotella 15w40?
Both these two engine oils are the winner here. If you go through the previous section where I explained and compared these two engine oils, it will be apparent that they both work better under different conditions. Still, you may find that Shell Rotella is a good competitor here since it produces premium category engine oils.
However, the Delo 15w40 engine oil will give you almost the same result as Rotella 15w40, but the Rotella gives high-quality additives and particles. Therefore, the oil change frequency and other particles are better than Delo. So, you can say that Rotella 15w40 wins here, although you have to pay more for these premium additives.
On the other hand, the Delo 15w40 is a good enough engine oil that gives you a perfectly balanced bundle of engine oil that can be purchased at a lower price. So, you can use it regularly in winter, whereas the Rotella will give you better performance in Hot weather.
Why Does Shell Rotella 15W40 Win?
The Shell Rotella 15w40 wins because of three reasons. Let’s explore these reasons and make them explicit.
- Premium Quality Additives & Particles: Since Shell Rotella is a premium category engine oil brand, it uses all high-quality additives to protect your engine or heavy-duty engine from wear, rust, and corrosion. Although it is better for hot weather, you will not find such premium category additives in other engine oils. So, quality additives & particles are the first reason Shell Rotella wins.
- Long Lasting: Another reason is long-lasting and changing frequency. You cannot use single engine oil for years or a long time. But the frequency of changing engine oil is tiresome work that you must consider while pouring or adding new engine oil. The shell Rotella 15w40 engine oil will give you superior performance and long-lasting using experience that is better than Delo 15w40 engine oil.
- Summer Performance: If you live in hot weather, you cannot skip Shell Rotella and expect any other brand to overperform this engine oil. You should go for Rotella 15w40 to get optimum engine performance with perfect viscosity engine oil. Summer performance is always a concern for people who drive heavy-duty trucks or vehicles. So, it’s the third reason why Shell Rotella 15W40 wins.
Why Does Delo 15w40 Lose?
The Delo 15w40 loses because of its additives, performance, and high-temperature performance. But you can declare the Delo 15w40 engine oil as a clear winner if you consider the cold weather, price, and average performance. If you have a heavy truck but want to invest less in regular engine oil, then the Delo 15w40 would be your best.
You will find an excellent engine performance in winter and will love to drive in snowfall too. Also, the price is competitive since you will not invest more in buying this regular engine oil. Considering these things, you may find Delo 15w40 is a clear winner.
Can I use Delo 15w40 instead of Rotella 15w40?
Yes, you can use Delo 15w40 instead of Rotella 15w40 since they come with similar additives and synthetic blends. But you will get less longevity than Rotella 15w40 since its premium-quality engine oil performs better than others.
Is Delo 15W40 a good Engine Oil?
Delo 15w40 is an excellent regular engine oil with quality additives and other particles to protect your engine from wear. So, you can use Delo 15W40 engine oil instead of any other engine oil.
Closing Words
The difference between Delo 15w40 vs. Rotella 15w40 engine oils are not many, but they are significant. To differentiate these two engine oils, you must consider the weather condition, price, and quality additives. If you love to use premium engine oil, you should go for Shell Rotella 15W40. Otherwise, the Delo 15w40 is a good choice.