2. What do Group I, II, and III mean, and what's so great about Group II and Group III?

  3. Why is VI important?
  4. What's so good about all-hydroprocessed base stocks?
  5. What is a base stock slate? Isn’t the slate the same as Base Oil Interchange (BOI)?
  6. What’s unique about Chevron’s Group II base oil slate?
  7. Can Chevron Group II base oils be used to substitute my current source of Group II base oils?
  8. Are Chevron and KIXX LUBO branded base oils technically interchangeable?
  9. Can I use my current additives with Chevron base oils? Can I use less additive?
  10. What about solvency of Group II base oils? Is it true that formulations that use these stocks have problems with rubber seals swelling properly?
  11. Why should I use Chevron base oils?
  12. Can you supply my location?


ISOCRACKING, ISODEWAXING and ISOFINISHING technology and catalysts are used in the sequence of refining processes employing hydrogen at high pressure to make high-quality lubricant base oils. ISOCRACKING technology is a hydrocracking process used to improve VI (Viscosity Index) and remove impurities. ISODEWAXING technology converts wax molecules into high quality lubricant components. ISOFINISHING technology is a final, high-pressure polishing process to improve the stability of Chevron base stocks.

Chevron invented the technology in 1994 and today virtually all Grp II and Grp III is made using some version of the isomerized dewaxing process. Customers who buy Chevron base oils will be the first to receive the benefits of our latest catalyst developments as we continue to improve and advance our technology.

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What do Group I, II, and III mean, and what's so great about Group II and Group III?

These groups, along with Group IV and Group V are broad categories of base stocks developed by the American Petroleum Institute (API) for the purpose of creating guidelines for interchanging base stocks when blending licensed engine oils. Typically, solvent-refined base oils fall into Group I, while hydroprocessed base stocks fall into Group II. Unconventional Base Oils (UCBOs) are more severely hydroprocessed to make Very-High VI stocks and are normally categorized as Group III. Group IV are polyalphaolefins, PAO's, and form the basis of many traditional synthetic lubricants. Group V are oils that do not fall into any of the first four groups. This chart, from API publication 1509 provides a simple way of remembering the properties of each of the Groups:

Group Sulfur, Wt% Saturates V.I.
I >0.03 and/or <90 80-119
II ≤0.03 and ≥90 80-119
III ≤0.03 and ≥90 ≥120
IV All Polyalphaolefins (PAOs)
V All Stock Not Included in Groups I-IV
(Pale Oils and Non-PAO Synthetics)

Group II+, though not an official API designation is a term used increasingly to describe Group II stocks of higher VI (112-119) and lower volatility than comparable group II stocks.

Group I oils contain high levels of sulfur and aromatics, which are compounds that can diminish performance. Group II & III oils have almost none of these impurities, which result in enhanced oxidation performance for fully-formulated lubricants. Thanks to Chevron's proprietary ISODEWAXING technology, Chevron's Group II and II+ base oils also have very low wax content, which delivers better low-temperature performance compared to many other base oils. Due to their high level of purity, Chevron Group II & II+ base oils provide additional benefits in crankcase applications. For example, in heavy-duty engines, motor oils made with Chevron base oils have demonstrated a soot dispersancy markedly higher than those made with Group I base oils.

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Why is VI important?

Viscosity Index (VI) measures the resistance of an oil to viscosity change as temperature changes. The higher the VI, the more stable the viscosity over a wide temperature range. In other words, the higher the VI, the less an oil will thicken as it gets cold and the less it will thin out at higher temperatures—providing better lubricant performance at both temperature extremes. This characteristic is essential to good performance in multi-grade engine oils, such as SAE 5W-30 or 10W-40. Our Group II+ base oil, 110RLV, has VI approaching that of Group III levels, enabling optimization of both cost and performance.

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What's so good about all-hydroprocessed base stocks?

Because all-hydroprocessed Group II & II+ stocks are manufactured with no solvent refining steps, they far surpass in purity base oils made in "hybrid" plants that maintain some solvent processing. In fact, they contain the lowest levels of impurities currently available in mineral-based oils, which, in turn, give them a significant performance advantage.

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What is a base stock slate? Isn’t it the same as Base Oil Interchange (BOI)?

According to the definition in API 1509, Appendix E and ATIEL code of practice, a base stock slate is a product line of base stocks that meets the definitions of the same base stock group, could have different viscosities, are from the same manufacturer, and has been demonstrated to be technically substitutable by other appropriate base stocks in the same slate.

A base stock slate is not the same as Base Oil Interchange (BOI), which is a set of established guidelines that facilitates substituting unlinked slates in particular formulations from one base oil slate to another. The ATIEL Code of Practice describes measures necessary to support the use of alternative base stocks in engine lubricants for which compliance with ACEA Oil Sequences has already been validated.

Base stocks within the same base stock slate or within linked base stock slates may be interchanged without additional testing.

Chevron’s Group II slate base stocks, 100R, 150R, 220R, 600R and 110RLV, have the same specifications and same product names and numbers regardless of source, just like additives made at different plants.

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What’s unique about Chevron’s Group II base oil slate?

All Chevron base oil plants, including the Richmond plant in California, Chevron’s JV plant in Yeosu, South Korea, and the future Pascagoula plant in MS, are not only ISO-9001 certified but are deliberately designed to make the same base oils. Through rigorous testing, Chevron-branded base oils from our California and South Korea facilities have been shown to be technically substitutable and therefore included in Chevron’s Global Group II Base Stock Slate.

When the new plant in Pascagoula, Mississippi, is producing base oils, additional testing will be carried out to demonstrate that the Pascagoula base stocks can also be included into Chevron’s Global Group II Slate. Chevron ensures that Chevron-branded base oils sold from our facilities continue to have this demonstrated fungibility.

Chevron’s base oil slate allows our customers to use the same approved formulations in different geographies with different Chevron supply sources. This benefit greatly simplifies formulation complexity as well as improves supply reliability.

Customers who purchase Chevron-branded products are supported by a long history of comprehensive technical support, product consistency and security of supply.

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Can Chevron Group II base oils be used to substitute my current source of Group II base oils?

Yes, in many cases,Chevron base oils can be substituted from your alternative Group II supply depending upon the particular application and necessary qualifications. Chevron base oils are approved for use in a very large portfolio of lubricant qualifications around the world. We work very closely with all of the additive companies as well as our customers in continuing to expand their cost effective lubricant formulations. When customers use Chevron base oils, they also gain the wealth of technical experience we can provide and excellent supply reliability that comes from a supplier with multiple plants and numerous hub locations.

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Are Chevron and KIXX LUBO branded base oils technically interchangeable?

No, they cannot be treated as the same. The Yeosu, South Korea plant produces two differently-branded base oils, Chevron and GS Caltex KIXX LUBO. Chevron and GS Caltex market their base oils separately, and the KIXX LUBO brand is not technically interchangeable with Chevron-branded base oils, which meet Chevron’s stringent specifications and performance requirements. Chevron’s substantial list of globally-approved lubricant formulations are based on Chevron-branded base oil properties and specifications. Chevron does not have any control of the GS Caltex KIXX LUBO product line, their specifications, or their product claims. KIXX-LUBO and Chevron-branded base oils are separate brands, so it is necessary to qualify lubricant products with those these two base stock slates using separate qualification programs.

Please always look for ‘Chevron’ and the suffix ‘R’ after the viscosity grade in the product labels for Chevron-branded base oils.

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Can I use my current additives with Chevron base oils? Can I use less additive?

Chevron base oils provide manufacturers many formulating options since they are compatible with a wide array of additives and additive systems. To fully leverage the exceptional properties of Chevron base oils and gain the highest performance levels available, the additive system should be optimized for all finished lubricant products. Any changes to treat rate should be discussed with your additive supplier. All the major additive suppliers are experienced in formulating with Chevron base stocks. In some cases, the higher purity and enhanced oxidation resistance of Chevron base oils may allow lower treat rates of specific additives in fully-formulated oils. For example, many products can use lower levels of oxidation inhibitors while maintaining or improving oxidation resistance. Or, a heavy-duty engine oil may be able to achieve better dispersancy of soot particles while using somewhat less dispersant. Of course it is important to test the fully-formulated lubricant to assure that the desired level of product performance is achieved.

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What about solvency of Group II base oils? Is it true that formulations that use these stocks have problems with rubber seals swelling properly?

While they do have slightly lower solvency than Group I base oils, Chevron Group II base oils exhibit a level of solvency compatible with the vast majority of additive components and systems. Furthermore, Chevron base oils have higher solvency than most synthetics and many Group III base oils. When properly formulated, lubricants made with Chevron base oils have proper seal swell characteristics. In a few applications, such as automatic transmission fluids, it may be necessary to add small amounts of a synthetic seal swell agent to achieve the proper performance.

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Why should I use Chevron base oils?

Chevron offers a unique combination of exceptional product performance, global reliability, and a global slate and comprehensive technical expertise.

Chevron base oils have a very long list of global qualifications and can be formulated with a wide variety of additives to meet both today’s and future industry specifications cost-effectively. To make sure our customers get the most from our premium base oils we provide technical support both before and after the sale. Chevron’s global availability helps customer’s optimize their supply chains as well as reduce formulation complexity. Finally, Chevron’s global product slate allows customers to use our products around the world without the need to requalify and improve reliability with fungible products available from multiple plants. All three of our plants have ISO-9001 certifications which ensure our plants are safe, reliable and produce good quality products.

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Can you supply my location?

With Chevron’s expansive logistics, terminal and distributor networks we have a significant amount of resources at our disposal to supply our customer’s product around the world, whether it be by marine, truck, rail or packaged. For questions about your specific location, please contact our Regional Sales Representative who will be best suited to answer your specific questions.

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