Shell Rotella T6 Vs Delo 400 SDE

Both contestants are completely synthetic heavy-duty engine oils prepared for four-stroke diesel engines with Delo being also compatible with four-stroke gasoline engines. The durability of vehicles’ emission control system is phenomenal because both of them meet the CK-4 API standard.

Both contenders meet the E9 ACEA standard which shows their compatibility with diesel particulate filters.

Shell Rotella (T6) is being manufactured with Triple Protection Plus Technology to provide superior wear protection and oxidation stability.

Check out the Comparison: Rotella T4 vs T5 vs T6

During high-temperature conditions, it delivers ultimate protection to diesel engines. It is appropriate for both new and old heavy-duty vehicles such as utility, delivery, and bus fleets.

Delo 400 SDE is designed with ISOSYN Advanced Technology to deliver ultimate engine cleaning and protection. It provides decent fuel economy by having long drain intervals.

It performs exceptionally in extremely cold weather conditions as well, by providing instant lubrication to the engine.

SpecificationsShell Rotella (T6)Delo 400 SDE
Viscosity GradesSAE 15W – 40, 0W – 40, 5W – 40SAE 15W – 40
AdditivesDispersants, Anti-wear additives, Cleaning detergents, Anti-oxidantsDispersants, Anti-wear additives, Cleaning detergents, Pour-point depressants, Anti-oxidants
Oil drainage (miles)6,000 – 8,00010,000 – 12,000
Engine TypeDieselGasoline / Diesel
ACEA StandardE9E9
ILSAC StandardGF-5GF-5
API StandardCK-4SN/CK-4

Viscosity Comparison

While comparing the viscosity of two engine oils, there are basically three important parameters to consider. The first parameter is the viscosity index, which can be explained as the occurrence of a change in the kinematic viscosity due to varying temperatures.

Delo would get more affected by the change in temperature since its index value is inferior to its opponent.

The pour point of engine oil is the last parameter to study is viscosity comparison. It’s the least temperature below which a lubricant would lose its competence to flow.

The relative value of pour point of Delo is lower than its counterpart and hence would lose its flowing ability later than its competitor.

Kinematic Viscosity is the absolute viscosity of a lubricant divided by its density at a certain temperature. The kinematic viscosity of Delo at low temperature is higher than its competitor but it is lower at high temperature.

ParameterShell Rotella (T6) 15W – 40Delo 400 SDE 15W – 40
Viscosity Index146134
Pour Point (o C)-39-43
Kinematic Viscosity @ 40o C103.8 cSt112 cSt
Kinematic Viscosity @ 100o C14.7 cSt14.6 cSt

Performance Impact on the Catalytic Converter

Sometimes when there is the condition of leakage in piston rings or seal breakage, engine oil gets seep inside the combustion chamber and burn out.

It results in the development of hazardous ash that have negative impact on the functioning of the catalytic converter.

The quantity of the ash formation depends upon the relative amount of zinc and phosphorous in lubricants.

Shell has a high amount of phosphorous and zinc in it than Delo. So in this respect, the best choice would be Delo for the sake of the catalytic converter’s wellbeing.

Engine OilContent of ZincContent of Phosphorous
Content in Shell Rotella (T6) 15W – 40, ppm                     1097       1000
Content in Delo 400 SDE 15W – 40, ppm851744

Reducing Sludge Formation

In the presence of oxygen, a process called oxidation happens when an engine oil stays in high-temperature conditions for an extended period, and the oil gets broken down on a molecular level.

After it gets broken down, it mixes with dirt, contamination, and moisture to make sludge and deposit.

Cleaning agents like magnesium, calcium, and sodium are being mixed into lubricants to keep the engine safe from sludge and deposit.

By analyzing the tested results shown in the table below, it is obvious that Delo is a superior choice since it holds more cleaning additives in it than Shell.

AdditiveQuantity in Shell Rotella (T6) 15W – 40Quantity in Delo 400 SDE 15W – 40
Magnesium, ppm83717
Sodium, ppm414
Calcium. ppm19641614

Protection of Oil Combustion

An inevitable phenomenon occurs in the engine which leads to the shortage of engine oil in it. It happens when the engine gets heated up and the engine oil in it gets vaporized and burn off.

The tendency of engine oil to evaporate and burn off depends upon its volatility and the flashpoint respectively.

Flashpoint is that specific temperature at which the vapor of a lubricant catches fire if an ignition source is provided to it.

Since the flashpoint of Delo is relatively lower than its opponent, it would burn more quickly. Hence, in hot weather, it would be wise to choose Shell for your engine.

Parameter Shell Rotella (T6) 15W – 40Delo 400 SDE 15W – 40
Flash Point249o C230 o C

Reducing Engine Deterioration

Majorly used additives for wear protection are phosphorus, zinc, molybdenum, and boron. So an engine oil that has a high amount of phosphorous, zinc, boron, and molybdenum in it would be highly operative against engine wear-off.

By the tested result given below, we can state that Shell encompasses more anti-wear additives than Delo and hence it has the superiority in this respect.

AdditiveQuantity in Shell Rotella (T6) 15W – 40 (ppm)Quantity in Delo 400 SDE 15W – 40 (ppm)

Comparing Oil Change Frequency

Due to the byproduct of combustion and oxidation inside an engine, the formation of hazardous acids occurs in it. These acids could be very harmful to the engine.

Alkaline-based additives are being added into engine oils to combat the acids. These additives counterbalance the acids and their neutralizing ability can be determined by a parameter known as the TBN (Total Base Number).

Once the basic additives in the engine oil lose their neutralizing ability, at that point engine oil is needed to be drained. Hence the oil change frequency of engine oil can be analyzed by its TBN.

As it is shown in the verified result below that Delo has high TBN in it than its opponent. It means that it would take a longer period for it to be drained. Hence the oil change frequency of Delo is relatively lower than Shell.

ParameterShell Rotella (T6) 15W – 40Delo 400 SDE 15W – 40
Total Base Number (mg KOH/g)7.610


  • Both of the engine oils are synthetic and prepared for heavy-duty engines.
  • The performance of catalytic converter would be affected more by Shell.
  • Delo provides superior sludge protection to the engine than its competitor.
  • Shell would be best suited for hot weather while Delo would be a better choice in a cold environment.
  • Shell provides better wear protection than its opponent.
  • Delo has a high kinematic viscosity at low temperature but it drops down with the temperature rise. It shows that it gets more affected by the temperature change.
  • The changing frequency of Delo is lower than its competitor.