Learn the Label Lingo Selecting the Best Oil for Your Vehicle

Choosing a motor oil today is no simple task when you are faced with shelves full of different brands. Determining the right oil for your vehicle can be confusing as you must decide which oil to use based on past experiences, choosing the brand your ‘Dad always used’, or leaving that decision to your service advisor or mechanic.

While the basic mechanics of an engine has remained the same over time, improvements in today’s engines require different levels of key motor oil components. These changes combined with emission standards have required motor oil manufacturers to make changes in formulations in order to adapt to the “new standard.” With what seems like a myriad of acronyms and numbers on the label, it can be difficult to determine which one is the best oil for your vehicle.

Setting the Standards

The Society of Automotive Engineers (SAE) sets the standards for motor oil performance in the United States. Motor oil in its various viscosities or thickness is tested on its resistance to flow when exposed to various degrees of temperatures found under normal vehicle operating conditions.

While there are mono-grade oils available on the market, multi-grade oils are more common based on the consistency of the viscosity when used in a range of temperatures and driving conditions. The cold temperature standard (W grades) indicates the maximum cold temperature viscosity. The second number after the dash is the warm temperature standard or minimum hot temperature viscosity.

Quality Symbol

The American Petroleum Institute (API) engine oil quality mark can be found on the motor oil label as a Certification Mark “Starburst” and Service Symbol “Donut.” Both symbols can help consumers identify quality motor oils, but each indicates different standards met by the respective oils. 

According to the American Petroleum Institute, motor oil displaying the API Certification Mark or “Starburst” signifies that, “The oil has met the current engine protection standard and fuel economy requirements of the International Lubricant Standardization and Approval Committee (ILSAC).”

The API Service Symbol or “Donut” stands for motor oils that fall under the API “S” Service or “C” Commercial categories. The letter “S” followed by another letter represents oils suitable for gasoline engines. The letter “C” followed by another letter or number denotes oil for diesel engines. To ensure companies who obtain API licensing for their products continue to follow industry technical specifications, the API Engine Oil program is supported by an enforcement program and continuous monitoring.

Royal Purple SN Licensed

Royal Purple’s API licensed motor oils are designed for new and vehicles under warranty, delivering superior protection and improving performance in gasoline and diesel engines. Royal Purple’s API SN licensed motor oils meet ILSAC GF-5 and Dexos1™1 performance requirements, and are fully compatible with mineral or other synthetic oils. Royal Purple SAE SN motor oils are available in 0W-20, 0W-40, 5W-20, 5W-30, 5W-40, 10W-30, 10W-40, 15W-40 and 20W-50 multi-grade weights. Royal Purple also produces mono-grade motor oils in SAE 30, SAE 40 and SAE 50 weights.

Royal Purple High Performance

To meet the needs of vehicle owners who want to maximize their vehicle’s performance and protect their high performance or modified engines, Royal Purple offers a high performance motor oil for vehicles no longer under warranty. The Royal Purple High Performance Street (HPS) series motor oils contain higher levels of zinc and phosphorus anti-wear additives and Royal Purple’s proprietary Synerlec® additive technology. This unique combination allows HPS to outperform leading synthetic and conventional motor oils. HPS motor oils are suitable for both gasoline and diesel engines and are available in: 5W-20, 5W-30, 10W-30, 10W-40 and 20W-50.

Knowing how to read the label of the motor oil bottle is important when it comes to choosing the best oil for your vehicle. Before you purchase your oil or take your vehicle in for an oil change, consult your owner’s manual for the recommended viscosity. Royal Purple suggests following the manufacturer’s oil change intervals when using API licensed SN oil. Consumers using Royal Purple HPS can improve engine performance and the overall life of their vehicle. If you have questions about Royal Purple products contact the Technical Department at rpautotech@royalpurple.com.