Question: I recently purchased a new 2011 Colorado 4x4 pickup, and I'm not sure what type of oil to use. After researching several websites, I found references to GF-4, GF-5, API CODE SM, and SN. All this seems confusing, and now GM has its own type of oil. Just what kind of oil and specs is recommended for this truck?
| 2011 Chevrolet Colorado Three Quarter Front View
Answer: SM and GF-4 are similar oil quality ratings published by two different organizations -- American Petroleum Institute (API) and International Lubricants Standardization and Approval Committee (ILSAC), respectively. Both SM and GF-4 have identified oil formulas approved by most manufacturers since 2005. But now we're converting to SN and GF-5, which are replacing the previous standard oil ratings. In your case, GM took it a step further by producing its own oil standard, going by the term "dexos 1" (dexos 2 for diesel engines). Beginning with the 2011 model year, General Motors is requiring that oils meeting the dexos 1 standard be used in its gas-powered engines, or risk a void powertrain warranty following an internal engine failure. GM states that dexos 1 improvements from GF-4 include: engine cleanliness, corrosion protection, sludge control, wear protection, aeration control, and fuel economy. Specifications don't require the oil to be synthetic, but I don't see anything other than a blend that meets the mark. That tells us it's going to be more expensive. Here's a site to view all the dexos 1 and 2 oils in production: www.gmdexos.com/licensedbrands.html. Your truck's preferred oil viscosity is 5W-30 -- or 0W-30 below 20 degrees Fahrenheit.
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