Originally Posted By: aimatdeer
Hello everyone, wondered what you guys thought. I have a 2014 chevy silverado with a 5.3. Factory fill is dexos blend and first four oil changes are free. Called my service department and asked if i paid an upcharge could i go to mobil 1 full synthetic. He really seemed to want me to stay with the dexos. Did not recomend going full synthetic and warned me once i do switch i can't go back. What do you guys think?
What's really synthetic? These days there is little difference between conventional and synthetic. In fact, API doesn't even accept "synthetic" as a valid technical term. API says '"Synthetic" is a marketing term, not a technical term.' Group III is further-refined Group II (so-called conventional) and GTL is further-refined Group III. They are all made from hydrocarbons (crude oil or natural gas in the case of GTL). Group IV, which is more synthetic in the sense that it's not directly extracted from crude oil or natural gas, is a little higher in quality than Group III and GTL. I don't think you can even find the true mineral oil, which is Group I, these days; so, the talk of synthetic could harm or change your engine is silly.
Shorter answer: You can go back and forth between synthetic and conventional and there will absolutely be no issues. On top of that, Mobil 1 and Mobil 1 Extended Performance are dexos1 oils and entirely approved by GM. It's not to mention that they outperform semisynthetic oils in every respect. Also, there is no conventional dexos1 even if you wanted to find one.