Your 2015 GMC Sierra 1500 with the 5.3L EcoTec3 engine uses Dexos1 Gen 2 certified SAE 5W-30 full-synthetic motor oil.
For the 2015 Sierra 1500, GM specifies Dexos1 Gen 2 5W-30 full‑synthetic oil, with a total capacity of about 8 quarts including the filter. Always follow the owner's manual for service intervals and use a high-quality oil that bears the Dexos certification to ensure proper lubrication and warranty compliance.
Oil specifications and capacity
These are the essential specifications to ensure you select the correct oil and have enough on hand for a full change.
- Oil type and certification: Dexos1 Gen 2 certified motor oil
- Viscosity: SAE 5W-30
- Formulation: Full synthetic recommended
- Oil capacity: Approximately 8 quarts (about 7.5–8.0 qt depending on filter and draining)
- Filter: GM/ACDelco oil filter or equivalent that meets OEM standards
Sticking to these specifications helps protect the engine and maintain performance over time.
Maintenance intervals and practical notes
Guidance on when to change the oil and how to perform a typical oil service.
- Consult the owner's manual for the recommended oil-change interval and driving conditions (normal vs. severe service).
- When changing the oil, warm the engine, drain the old oil completely, and cleanly replace the oil filter.
- Refill with Dexos1 Gen 2 5W-30 full-synthetic oil to approximately 8 quarts, then check the level with the dipstick and top up if needed.
- Dispose of used oil at an approved recycling facility and reset any maintenance indicators as applicable.
Adhering to the recommended oil type and capacity, along with the correct change interval, helps ensure long-term reliability of the 5.3L EcoTec3 engine.
Summary
Bottom line: For a 2015 GMC Sierra 1500 with a 5.3L EcoTec3 engine, use Dexos1 Gen 2 5W-30 full-synthetic oil, about 8 quarts including the filter, and follow GM's maintenance schedule. Choose OEM or equivalent quality filters and follow proper disposal guidelines for used oil.