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What Is Dexos1?

What is dexos 1?

Many have asked this question and in this article, we hope to get you an answer.

Approximately every 5 years, a new service category is placed on engine oil. The reason behind this is that auto manufacturers are under constant pressure to reduce emissions, offer better protection against sludge, and increase fuel economy. In 2011, the American Petroleum Institute (API) Service Category SN and International Lubricants Standardization and Approval Committee (ILSAC) GF-5 were introduced as the latest Resource Conserving service categories. API and ILSAC have set the standards for oil for 60 years. API is recognized as an American standard and ILSAC is an internationally recognized specification.

In 2011, GM introduced their own stand-alone specification, “dexos,” to meet the stringent requirements for their engines. The difference in a GF-5 approved oil and dexos approved oil is testing. GM dexos approved oils require proprietary tests that are not included in current industry standards. GF-5 is tested to meet API specifications. GF-5 oils are available in conventional, synthetic blend, and full synthetic versions, whereas dexos has to have some level of synthetic in order to meet GM’s stringent requirements. This leads one to wonder what will happen if they do not use dexos where it is required.

GM claims that severe damage can be done to your engine if a dexos-approved oil is not used and there is a possibility your warranty can be void. GM’s newer model vehicles now use oil life monitors which anticipate longer drain intervals based on the use of dexos-approved lubricants. Using a non-dexos-approved oil can result in the use of an oil that will not have a service life that is programmed into the oil life monitor. This can give the driver a false sense of security that the oil in their engine is still good when in fact it isn’t. So always follow what is specified in your owner’s manual when choosing your motor oil. Be sure that what you are purchasing meets the proper API, ILSAC, or in this case dexos1 specification.

Petroleum Service Company offers 3 products that are fully licensed and approved to meet the stringent requirements of GM’s dexos1 specification: Mobil 1 5w-30, Kendall GT-1 dexos1 5w-30, and Coastal dexos1 5w-30 are available in drums and cases. Click on the listed products for current pricing and Product Data Sheets.

John Gula


  • The info. on Dexos 1 vs. just GF-5 SAE spec oils is important. Many consumers do not read their new car owner’s manual which tells them exactly which oil specs are required to protect their engine and maintain their new car warranty. Disingenuous purveyors of oils often say their oil product is “suitable” for use under a certain specification. “Suitable” means the product has never been Certified to meet the specs and thus does not meet your new vehicle warranty requirements even though unscrupulous purveys particularly of “boutique oils” will try to get you to buy their un-certified oils. If you value your new car warranty, use only the oils that have been Certified to meet the warranty requirements.
    Also take note that many Quick Change Lube shops do NOT even know what the proper oils are for many cars, especially Diesels and European models such as Porsche, Audi, BMW, Mercedes, VW, etc. and as a result they could use an improper oil that will cause excessive engine wear or complete engine failure.

  • I have been in the Automotive Service side of this business for over 20 years and have seen some desperate acts by Automobile Manufacturers. After extensive research of this matter I believe this is an easy way for GM to wiggle out of a system which profits no one other than GM. They come up with this “OIL LIFE MONITOR” and when it is discovered that it does not meet “CODE” they come up with an oil that will “MAKE IT WORK OUT”. As soon as one of our innocent customer comes in for an oil consumption problem they point the finger at the aftermarket facility blaming them for not properly informing the public. I have had thousands of customers concerned with oil consumption problems and I could count on one hand the folks that have actually had a dealer help them with their repair costs that were not fully recalled vehicles. Sad…just sad.