GM dexos™ Engine Oil Increases Engine Efficiency New for the 2011 model year, GM will introduce ACDelco dexos™1 certified engine oil as a factory fill and service fill for its gasoline engines worldwide. The new engine oil specification has been developed to help meet the increased demands for enhanced engine efficiency. dexos™ oil helps deliver increased fuel efficiency and reduced engine emissions. dexos™ is a GM proprietary engine oil specification that has been designed to:
- Further improve fuel economy (to meet future Corporate Average Fuel Economy, CAFE, requirements) and fuel economy retention through improved viscometric properties that create less friction in the engine, which allows the oil to maintain its fuel economy benefits throughout the longer life of the oil
- Provide a more robust formulation for added engine protection that offers improved oxidation and deposit-forming tendencies and aeration performance, which enables fuel-saving devices, such as January / February I 2011 January / February 2011 ACDelco News Page 2 Variable Valve Timing, to work optimally
- Support GM’s Oil Life Monitoring System (OLMS) by resisting degradation between oil changes
- Ensure worldwide availability of equal quality oil while reducing the duplication of a large number of internal GM engine oil specifications, replacing GM specifications GMLL-A-025, GM6094M and GM4718M. dexos™1 also is backward compatible for older vehicles; however, the owner manual oil specification in prior model years remains acceptable.
The dexos™ specification includes two classifications.
- GM will require dexos™1 for global factory fill in spark ignited engines worldwide and service fill for gasoline engines worldwide. It will replace the GM6094M specification for most GM gasoline engines.
- dexos™2, required for diesel engines as well as a service fill for gasoline engines in Europe, was introduced in Europe late last year.
In addition to GM dexos™, a new International Lubricants Standardization and Approval Committee (ILSAC) standard, GF-5, was introduced in 2010. There is a new API engine oil service category – SN Resource Conserving. The current GF-4 standard was put in place in 2004. The GF- 5 standard will use a new engine fuel economy test, called Sequence VID (six D), which provides a statistically significant increase in fuel economy versus the Sequence VIB (six B) test that was used for GF-4. Like dexos™, the new ILSAC GF-5 standard will call for more sophisticated additives.
It’s expected that all dexos™1 approved oils will meet GF-5. However, not all GF-5 engine oils will necessarily meet the dexos™ specification.
Since CAFE standards were first introduced in 1974, the fuel economy of cars has more than doubled, while the fuel economy of light trucks has increased by more than 50 percent. Proposed CAFE standards call for a continuation of increased fuel economy in new cars and trucks. To meet these future requirements, all vehicle operation aspects are being looked at more critically than ever before.
New technology being introduced in GM vehicles designed to address vehicle efficiency and fuel economy include direct injection, cam phasing, turbocharging and Active Fuel Management. The demands of these technologies on engine oil also are taken into consideration when determining new oil specifications. Active Fuel Management, for example, can help to achieve improved fuel economy, however, alternately starting and stopping cylinders puts a lot of stress on engine oil.
To meet tough fuel economy mandates, the industry will shift toward lower viscosity oils. Testing has shown that thinner 0W-20 oil, for example, can provide as much as a 4-percent improvement in fuel economy over 15W-40 oil.
dexos™1 will be offered in these viscosities: SAE 0W-20, 5W-20, 0W-30 and 5W-30. dexos2™ will be available in SAE 5W-30, 0W-40 and 5W-40. Please check the appropriate vehicle owner manual for the proper viscosity grade.
Increased Service Intervals
To help reduce the consumption of oil while maintaining proper engine protection, many GM vehicles equipped with the GM OLMS have a maximum oil change interval that is much longer than what was considered a normal interval just a few years ago.
ACDelco News Page 3 If all GM vehicle owners follow the OLMS intervals in their vehicles as intended, GM estimates that more than 100 million gallons of oil could be saved annually.
The second generation OLMS will rely on significantly more engine operating information than the current system, which, combined with dexos™ certified oil, could allow a significant extension of the maximum oil change interval. dexos™ specifications call for improved oil robustness to support extended drain intervals over a vehicle’s lifetime.
When the OLMS determines that an oil and filter change is needed, the driver is notified by a Change Oil message on the instrument panel. The oil change should be performed within 600 miles (1,000 km). The OLMS must be manually reset when the oil is changed.
dexos™1 Availability: Currently, ACDelco Synthetic Blend dexos™1 5W30 engine oil is available through the GM Oil Program in 55 gallon drums (which can be pumped into bulk tanks). Quart-size packaged product is now available. Orders may be placed through your local ACDelco oil distributor http://www.jackmaxton.com.
More Information can be found at