The 2018 GMC 6.2L V8 typically requires about 8 quarts of engine oil with a new filter, which is roughly 7.5–7.6 liters, using Dexos1 Gen 2 0W-20 synthetic oil.
In this article, we break down the official capacity, how it can vary depending on the service performed, and how to verify the correct oil level after a fill. We also cover the recommended oil grade and practical tips for maintaining proper levels in different conditions.
Oil capacity at a glance
Here are the standard oil capacities you’ll encounter when servicing the 2018 GMC 6.2L V8, assuming a full oil change with a new filter. Note that capacities can differ slightly by exact engine variant or filter size.
- With a new oil filter (typical full change): 8 quarts (about 7.6 liters)
- Without a filter (drain-and-fill without filter replacement): 7 quarts (about 6.6 liters)
After pouring in the oil, always inspect the level with the dipstick and run the engine briefly to circulate the oil before rechecking. Refilling to the proper level helps avoid overfill or underfill issues.
Oil type and viscosity recommendations
Using the correct oil grade is essential for performance and longevity of the 6.2L engine. The GM 6.2L V8 used in 2018 GMC trucks generally requires a Dexos1 Gen 2 certified synthetic oil, with a viscosity of 0W-20 in most climates. Always confirm the exact specification in the owner’s manual or under-hood labeling for your vehicle's trim and regional requirements.
- Oil type: Dexos1 Gen 2 synthetic
- Viscosity: 0W-20 (primarily recommended for most regions and climates)
- Note: Always follow the manual for region-specific recommendations and any updates from GM
Using the recommended oil and the correct quantity helps maintain engine efficiency, fuel economy, and warranty compliance. If you’re unsure about your particular vehicle variant, consult the owner’s manual or contact a GM dealer for precise guidance.
Practical tips for a smooth oil change
Before beginning an oil change, prepare the right tools and materials, warm up the engine slightly for easier draining, and ensure proper disposal of old oil. Keep these steps in mind:
- Warm engine to about 180°F (82°C) to improve drainage
- Use the correct filter and OEM or equivalent grade
- Replace the oil drain plug washer if applicable
- Recheck level after a short idle and warm-up cycle
Following a careful process helps ensure an accurate oil level and preserves engine health over the long term.
Summary
For the 2018 GMC 6.2L V8, plan on about 8 quarts (roughly 7.5–7.6 liters) of Dexos1 Gen 2 0W-20 synthetic oil for a full oil change with a new filter. Without replacing the filter, the capacity drops to about 7 quarts (approximately 6.6 liters). Always verify the exact capacity and oil specification in your owner’s manual or at a GM service center, and check the level with the dipstick after refilling to ensure proper lubrication. Regular maintenance with the correct oil supports engine performance and longevity.