The correct oil depends on which engine you have. In general, GM’s Dexos-certified oils are required for the 2020 Sierra 1500, with most gasoline engines calling for Dexos1 Gen 2 in a 0W-20 viscosity, while the diesel Duramax uses DexosD in a 5W-40 grade. Always verify with the owner’s manual or the door sticker for your exact configuration.
Engine-specific oil guidance
Use the following oil types as a quick reference based on the Sierra’s powertrain options. The exact specification (including viscosity) can vary by climate and model year, so check your manual for your particular build.
- 5.3L V8 (gasoline) — Dexos1 Gen 2, 0W-20, full synthetic.
- 6.2L V8 (gasoline) — Dexos1 Gen 2, 0W-20, full synthetic.
- 2.7L Turbo (gasoline) — Dexos1 Gen 2, typically 5W-30, full synthetic.
Note: Oil capacity varies by engine and configuration. Always refer to the owner’s manual for the exact oil capacity and service interval.
Diesel option
The 2020 Sierra 1500 with the 3.0L Duramax diesel uses a different lubricant standard due to its diesel-specific requirements.
- 3.0L Duramax Diesel — DexosD, 5W-40, full synthetic.
For diesels, using a DexosD-certified oil ensures compatibility with the engine’s lubrication and emission-control systems. Capacity and interval details are engine-specific and should be confirmed in the manual.
In practice, the key takeaway is to choose Dexos-certified oil appropriate to your engine: 0W-20 Dexos1 Gen 2 for most gas engines, 5W-30 Dexos1 Gen 2 for the 2.7L turbo, and DexosD 5W-40 for the 3.0L Duramax diesel.
Why the distinction matters
Oil specification aligns with engine design, piston cooling needs, and turbocharging behavior. Using the wrong oil can impact lubrication efficiency, fuel economy, and warranty coverage. If you’re unsure which engine powers your Sierra, consult the window sticker (EPA/engine code), the owner’s manual, or contact a GMC service advisor.
Summary: The 2020 GMC Sierra 1500 requires Dexos-certified oil tailored to the engine: 0W-20 Dexos1 Gen 2 for most gasoline engines (5.3L, 6.2L) and 5W-30 Dexos1 Gen 2 for the 2.7L turbo; and DexosD 5W-40 for the 3.0L Duramax diesel. Always verify the exact specification for your specific vehicle.
What oil is best for a GMC Sierra 1500?
SAE 5W-30 Dexos1
The GMC Sierra 1500 oil type depends on the kind of engine you have. For a gasoline engine, we recommend SAE 5W-30 Dexos1 full synthetic oil. If you want protection for really low temperatures, consider 0W-30 oil.
Can I run 5W-30 instead of 0W-20?
Modern engines designed for 0W-20 oil require specific viscosity for optimal performance, and using thicker 5W-30 oil may compromise efficiency while potentially voiding manufacturer warranties.
What is the best oil for a 5.3 L V8?
Most recent Silverado 1500 models with the 5.3L V8 or 6.2L V8 engines typically use SAE 0W-20 full synthetic motor oil.
How much oil does a 2020 GMC Sierra 5.3 L take?
8 quarts
5.3L V8 – 8 quarts.