1. You can’t switch back to mineral oil after using a synthetic oil

Switching back to conventional oil from synthetic is absolutely safe. You can change from the 5W-40 synthetic oil you used in the winter to a 15W-40 conventional oil in the spring. We offer Shell Rotella T4 15W-40 conventional oil and Shell Rotella T6 15W-40 full synthetic if you want the added benefits of synthetic oil technology.

“During colder months, it's a good idea to switch to a lower viscosity oil – in this case, synthetic oil – to provide improvements in engine stability,” explains Karin Haumann, OEM Technical Manager for Shell Lubricants.

Haumann adds: “Because a synthetic oil can meet the same OEM specification as a conventional oil, the question is, are you willing to relinquish the inherent benefits a full synthetic product can give you?” With the proven benefits of synthetic, you can use it in your engine all the time.

2. Synthetic oil is too expensive

While synthetic blend and full synthetic oils may cost more upfront, the benefits they provide make them worth the investment. “The benefits Shell Rotella® synthetic motor oil provides in terms of engine protection, longer oil drain intervals, and equipment durability over the lifetime of the engine easily outweigh the cost,” said Haumann.

Shell Rotella® T6 Full Synthetic engine oils provide protection that can save money with enhanced fuel economy capability, without compromising engine protection or durability.

Key performance and fuel economy benefits of synthetic include:

  • Lower oil consumption to help reduce maintenance costs 
  • Increased protection against oxidation for increased fuel economy 
  • Excellent corrosion control to help protect key engine parts 
  • Low Ash formulation for emissions system compatibility

3. Only newer engines need synthetic oils

Synthetic engine oils are designed to provide improved protection for a range of extreme working conditions in new and older engines. Whether you’re stop-and-go driving or working in freezing cold or desert heat, synthetic engine oils are designed to:

  • Improved engine protection 
  • Promote engine cleanliness 
  • Keep operating temperatures cooler 
  • Lubricate the engine quickly when starting in cold weather

If your engine is designed for higher performance that will put higher stress on the engine and the oil. It’s best to have a synthetic oil that's better at withstanding that stress.

“It’s well known that synthetic products can protect engines better than conventional oils,” says Haumann. “Most new vehicles require a XW-40 or lower synthetic blend type oil because it improves startability in heavy-duty engines and offers real advantages in fuel economy.”

Shell Rotella oil

4. You can't change brands of engine oil

As long as the specifications and approvals of the new oil meet what is required by your engine’s manufacturer, you can switch between brands with no issues. Though several brands of oil may meet the same industry and OEM specifications, they often have different performance levels.

Shell Rotella® offers a complete portfolio of synthetic and synthetic blend heavy duty engine oils that are suitable for virtually all modern low-emission heavy duty engines and older hard working diesel engines. With its wide range of specifications, and approvals from many of the world’s leading engine makers, the oils are an excellent choice for on-highway fleets, general haul, construction, agriculture, public-transport operators and diesel pick-up trucks.

Drain the oil and you can change brands. Shell Rotella meets or exceeds current CK-4 and other standards

5. High viscosity oil is best

With Shell Rotella T5 10W-30 synthetic blend, you get the strong wear protection of a 15W-40 with the added benefit of fuel savings.1

In addition, Shell Lubricants has introduced Shell Rotella® T6 10W-30 full synthetic heavy duty engine oil, which provides the benefits of a full synthetic engine oil in the fastest growing viscosity grade for diesel-powered vehicles. The versatile oil offers fuel economy benefits and excellent engine protection for hard working trucks.

Shell Rotella® T6 full synthetic engine oils provide protection that can save money with enhanced fuel economy capability, without compromising engine protection or durability. The oils also perform extremely well in heavy duty diesel engines even in extreme temperatures, meeting and exceeding industry performance standards.

Shell Rotella® T6 15W-40 Full Synthetic is for diesel engine drivers that prefer the higher-viscosity but still want the benefits of synthetic technology.

See Shell Rotella Products


1 Compared to Shell Rotella T4 15W-40

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