#2 · Feb 28, 2018 UtahTransplant said: Just bought my first SSR, sell grinning! Local Chevy dealer uses Dexos and says it's good oil for my 2005. Is it or should I insist on Mobil 1? :| When it comes to (brands) of oil and who all likes which one, there are multiple choices and preferences. Please note: GM dexos 1 Gen 3 engine oils exceed the performance of GM dexos 1 Gen 2 engine oils and are backward compatible, therefore vehicles that previously used GM dexos 1 or GM dexos 1 Gen 2 will use a GM dexos 1 Gen 3 or GM dexos R licensed engine oil of the appropriate viscosity grade at their next oil change. Is Mobil 1 Advanced Full Synthetic Dexos approved? For drivers of diesel vehicles, Mobil 1 ESP X2 0W-20 provides the reassurance that it carries the dexosD approval for diesel engines. This unique specification has been developed by General Motors (GM) exclusively for their own diesel engines. I have been using Mobil 1 Extended Performance 5w-20 oil since I got the car in 2015 since it was Dexos -1 certified. I no longer see the Dexos-1 license on the bottles of this oil and Mobil 1's website no longer shows 5w-20 as certified Dexos-1 though 0w-20 and 5w-30 remain certified. Mobil 1 Castrol Edge (Black Jug) Valvoline Advanced All of these oils are GF-6 or GF-6a, but I recently noticed that the 5w20 viscosity is not Dexos approved. However, they are Dexos approved for 5w-30 and 0w-20. Makes me wonder why? Is 5w-20 becoming an obsolete oil viscosity? (I don't think so) Yes, Mobil 1 high mileage 0w20 is Dexos approved. What Oil Brands are Dexos Approved? There are a few different oil brands that are Dexos approved, but the most popular ones are Castrol, Mobil 1, and Valvoline. These oils all meet the dexos1 specification, which is a GM specific oil standard. Applications Mobil 1™ 5W-30 is recommended by ExxonMobil for all types of modern gasoline-powered vehicles, including high-performance turbocharged, supercharged, multi-valve fuel injected engines found in passenger cars, SUVs, light vans and light trucks. O.k. I'm ready to change the oil, the cruze is got 2000 km ( 1600 miles ). I know it's pre-mature, but I always remove factory oil within 2000 km, and go with the OLM after that, using synthetic oil. The problem I'm facing is, I can't find new stock of mobil1 with the dexos approved label on. I In short, the answer is yes. Multiple oils can meet dexos specifications but follow specific instructions. If you own a used car that is new to you, it will be better to change your oil to the brand you prefer. Then you have to change your oil again in 500 to 1000 miles. Three of our 5W-20 oil carry the dexos®1 approval specified for General Motors vehicles. *The dexos® specification and trademark are exclusive to General Motors, LLC. What do the numbers in 5W-20 mean? The numbers refer to the weight and thickness, or viscosity, of the oil. Motor oil gets thicker when it's cold and thinner when it heats up. x9Zrbo.