2021 GMC Sierra 2500HD Oil Capacity & Filter

The 2021 GMC Sierra 2500HD requires 6.0 quarts (5.7 liters) of 5W-30 dexos1 Gen3 oil for the 6.6L L8T gasoline engine, or 10.0 quarts (9.5 liters) of 15W-40 or 5W-40 API CK-4/FA-4 oil for the 6.6L L5P Duramax diesel engine.

Quick Answer

6.6L L8T Gasoline Engine:

• Oil Capacity: 6.0 quarts (5.7 liters)
• Recommended Oil: 5W-30 dexos1 Gen3 full synthetic
• Oil Filter (OEM): PF63 (ACDelco)
• Oil Filter (Aftermarket Cross-Reference):
  • Fram: PH10575
  • Wix: 57045
  • Mobil 1: M1-113A

6.6L L5P Duramax Diesel Engine:

• Oil Capacity: 10.0 quarts (9.5 liters)
• Recommended Oil: 15W-40 or 5W-40 API CK-4/FA-4 (Consult your owner's manual for specific viscosity recommendations based on climate).
• Oil Filter (OEM): PF2232F (ACDelco)
• Oil Filter (Aftermarket Cross-Reference):
  • Fram: CH12803
  • Wix: WA10173
  • Mobil 1: M1-210B

Capacity by Engine Option

Oil Change Interval

The oil change interval for your 2021 GMC Sierra 2500HD can vary significantly based on driving conditions and engine type.

• Normal Duty: For vehicles operating under normal conditions (e.g., highway driving, light towing), an oil change is typically recommended every 7,500 miles or 12 months, whichever comes first, for the gasoline engine. For the Duramax diesel, the interval can extend up to 10,000-12,000 miles or 12 months under normal conditions, but always follow your vehicle's Oil Life Monitoring System.
• Severe Duty: If your driving involves frequent short trips, extensive idling, heavy towing, extreme temperatures, or dusty conditions, your vehicle is considered to be operating under severe duty. In such cases, the oil change interval should be shortened to around 3,000-5,000 miles or 6 months for the gasoline engine, and potentially 6,000-8,000 miles or 12 months for the diesel, or as indicated by the Oil Life Monitoring System.

Always adhere to the vehicle's Oil Life Monitoring System (OLMS) and consult your owner's manual for the most accurate and up-to-date recommendations.

Drain Plug Torque

It is crucial to properly torque your drain plugs to prevent leaks and damage.

• 6.6L L8T Gasoline Engine: The oil drain plug torque is typically 25-28 lb-ft (34-38 Nm). A new drain plug gasket/crush washer should be used with every oil change.
• 6.6L L5P Duramax Diesel Engine: The oil drain plug torque is typically 37 lb-ft (50 Nm). A new drain plug gasket/crush washer should be used with every oil change.

Always confirm these specifications with your service manual for the exact torque values for your specific model.

How to Change the Oil

1. Warm Up Engine: Drive the truck for a few minutes to warm the oil, allowing it to drain more easily.
2. Lift and Secure: Safely lift the front of the truck using a jack and secure it with jack stands. Ensure the vehicle is level.
3. Locate Drain Plug: Place a suitable oil drain pan beneath the oil pan. Remove the drain plug with the correct wrench.
4. Drain Oil: Allow all the old oil to drain completely. This can take 10-15 minutes.
5. Replace Drain Plug: Install a new crush washer on the drain plug and reinsert it into the oil pan. Torque to the specified value.
6. Replace Oil Filter: Carefully unscrew the old oil filter. Apply a thin coat of new oil to the gasket of the new filter before screwing it on by hand until snug, then an additional 3/4 turn (or refer to filter instructions).
7. Add New Oil: Remove the oil fill cap on top of the engine. Using a funnel, slowly add the recommended quantity and type of new oil.
8. Check Level: Start the engine and let it run for a few minutes to circulate the new oil. Turn off the engine, wait a few minutes, then check the oil level with the dipstick. Add more oil if necessary.
9. Reset Oil Life Monitor: Follow the instructions in your owner's manual to reset the Oil Life Monitoring System.

Common Issues / Tips for the 2021 Sierra 2500HD Generation

• Duramax Fuel Filter: It's recommended to change the fuel filter on the L5P Duramax at each oil change, or at least every other oil change, especially if using biodiesel blends.
• DEF System Maintenance (Diesel): Ensure you are using high-quality Diesel Exhaust Fluid (DEF) and keep the tank adequately filled. Issues with the DEF system can trigger check engine lights and even put the truck into "limp mode."
• Gasoline Direct Injection (L8T): While the L8T is a robust engine, like most GDI engines, there can be potential for carbon buildup on intake valves over very high mileage. Regular oil changes with quality synthetic oil can help mitigate this.
• Oil Pan Access: For the Duramax, the oil pan is relatively easy to access. For the gasoline engine, ensure you have appropriate tools and extensions, as access might be slightly more confined.

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