This is an interesting read:
General Motor's engine oil logo, Dexos 1. GM
If you're thinking about buying a 2011 General Motors vehicle the oil in your new vehicle's engine will be new as well, meeting a recently unveiled specification called "dexos 1."
Oils that meet the dexos 1 (yes, with a lowercase “d”) standard provide some real benefits. However, when it comes time for that first oil change, expect a 25-30 percent cost increase -- which could be about the same as choosing pure synthetic oil.
Further, GM says that if a customer has an engine failure that is traced to oil or lubrication issues, and if the customer does not use dexos 1 oil in their gasoline-powered GM vehicle, that act alone could void the warranty. The same goes for GM vehicles with diesel engines, which use a diesel-specific “dexos 2” oil blend.
Not Just GM
But let’s not be too quick to admonish GM for requiring this new oil or speculate that this is bound to drive away potential customers. The reality is that the cost for an oil change will be going up for everyone. That’s because we're in the launch period for a new-and-improved oil standard, which will eventually be commonplace across the industry.
Superseding the current standard, called “GF-4,” will be oils made to the new “GF-5” specification. These are beginning to show up in auto parts stores and oil change shops across the country this fall. Manufacturers other than GM are expected to begin factory-filling vehicles with GF-5 oils starting with 2012 models.
The new GF-5 performance specification was developed by the International Lubricants Standardization and Approval Committee (ILSAC) with input from automakers, oil refiners, and oil additive manufacturers. Like the GM-specific dexos 1 oil, GF-5 oils deliver better performance but cost more. Expect to pay about 15-20 percent over comparable GF-4 oils.
The new GF-5 and GM dexos oils are superior to most non-synthetic oils. The new formulations are also backwards compatible, meaning they will work in engines that have used older oil formulations.
How More Expensive Oils Can Save Money
Dexos and GF-5 oils are more expensive than prior oil formulations because these new oils deliver superior performance. Oil makers start with higher-quality base oil and then add more additives, which make them more expensive. Additives can make up as much as 30 percent of a typical quart of oil.
These high-performance oils can pay for themselves, but not how you might think. Many of these oils will advertise the benefit of "higher fuel economy." The claim isn't false because dexos and GF-5 oils do reduce internal engine friction that will improve fuel efficiency. Unfortunately the gains will be so small -- less than one percent -- that the average driver will never notice.
The real payback comes from extending the time and mileage between oil changes. Dexos and GF-5 oils allow drivers to drive more miles between oil changes without needing to worry about a loss of lubrication qualities, the buildup of sludge, or damage to sensitive emission control devices. Depending on driving habits, oil changes could extend beyond 10,000 miles.
While that may be heresy compared to the 3,000-mile oil change interval your local shop recommends, it’s the new reality of oil change intervals. Thanks to the use of in-vehicle oil life monitoring and these new oil formulations, there’s no longer one specific mileage interval to adhere to. In other words, changing your oil every 3,000 miles will likely lead to wasting oil by replacing it before it is actually necessary.
Both dexos 1 and GF-5 oil specifications also offer more comprehensive protection for engines, including the latest generation of turbocharged engines and those that run on ethanol (E85). Turbochargers and E85 each demand specific characteristics from engine oils. Resistance to heat is especially important for turbo engines, while protection against rust is critical for vehicles running on E85. In other words, running the right oil might mean the difference between an engine that lasts hundreds of thousands of miles, and one that doesn't.
The dexos oil also has some unique properties that General Motors engineers required. One characteristic is better resistance to aeration (the whipping of air bubbles into the oil). Some GM engines with variable camshaft timing use engine oil as a hydraulic fluid to move components within the engine. If air bubbles are in the oil, components actuated by engine oil will not move as they were designed to, limiting engine performance and efficiency.
Here’s the bottom line: use the oil recommended for your vehicle and you won’t have a problem.
