# 2012 GMC Sierra 1500 - Switching oil types **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** gmc\ **Created:** [December 19, 2018, 4:45pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115 "2018-12-19T16:45:24Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![NicoleCrandall](https://avatars.discourse-cdn.com/v4/letter/n/b5e925/32.png) [@NicoleCrandall](https://community.cartalk.com/u/NicoleCrandall)\ **Post date:** [December 19, 2018, 4:45pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/1 "2018-12-19T16:45:24Z")
Is it a bad idea to switch between synthetic motor oil to standard motor oil and back to synthetic? ---
**Author:** ![shanonia](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@shanonia](https://community.cartalk.com/u/shanonia)\ **Post date:** [December 19, 2018, 5:23pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/2 "2018-12-19T17:23:24Z")
No. The viscosity is more important. If the book says 5W20, use 5W20, for example. ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [December 19, 2018, 5:29pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/3 "2018-12-19T17:29:28Z")
You can go back and forth and mix all you want. It’s perfectly fine. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [December 19, 2018, 5:29pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/4 "2018-12-19T17:29:28Z")
There was (what I suspect was an urban myth, but will let the more knowledgeable people comment) the belief that synthetic would cause seals to swell and returning to conventional the seals would shrink and cause oil leaks. May have been started by makers of full synthetic oils, I doubt it is true. ---
**Author:** ![edb1961](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/edb1961/32/122_2.png) [@edb1961](https://community.cartalk.com/u/edb1961)\ **Post date:** [December 19, 2018, 6:20pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/5 "2018-12-19T18:20:54Z")
Your 2012 requires Dexos-1 specification motor oil, so you will have to use an Dexos licensed semi-synthetic or full synthetic motor oil. I don’t believe any conventional oils meet the spec. Ed B. ---
**Author:** ![shanonia](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@shanonia](https://community.cartalk.com/u/shanonia)\ **Post date:** [December 19, 2018, 6:30pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/6 "2018-12-19T18:30:32Z")
Let the owners manual rule: if there’s no non-synth that meets the spec, stay away from any non-synth. It’s a more recent phenomenon, that more and more cars have a spec that is only met by synth or a blend, but believe what the carmaker says. ---
**Author:** ![asemaster](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@asemaster](https://community.cartalk.com/u/asemaster)\ **Post date:** [December 19, 2018, 9:09pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/7 "2018-12-19T21:09:00Z")
There is no standard motor oil that meets the requirements for your engine. Any oil you use must have the “dexos” label on it, and that means a synthetic blend or full synthetic that meets the dexos specification. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [December 19, 2018, 11:42pm UTC](https://community.cartalk.com/t/2012-gmc-sierra-1500-switching-oil-types/131115/8 "2018-12-19T23:42:05Z")
If you can wait for Costco’s next price reduction on Mobil-1, you will be able to snag a **Dexos** -certified oil that is substantially cheaper than anyone else’s price.