2020 GMC Sierra 2500HD Oil Capacity & Filter Guide

The 2020 GMC Sierra 2500HD takes either 8.0 quarts of oil for the 6.6L V8 gas engine or 10.0 quarts for the 6.6L Duramax turbo-diesel V8, both including the oil filter replacement. As an ASE-certified master technician, I've serviced countless heavy-duty trucks, and knowing the exact specifications for your Sierra 2500HD is the foundation for keeping these workhorses on the road. Below is the complete breakdown of oil capacities, filter cross-references, and torque specs for the 2020 model year.

Quick answer

Depending on which powerplant sits under the hood of your 2020 GMC Sierra 2500HD, your specs will vary significantly:

For the 6.6L V8 Gas (L8T):

• Oil Capacity: 8.0 quarts (7.6 L) with filter
• Recommended Weight: 5W-30
• Oil Specification: dexos1 Gen 2 / Gen 3 or API SP
• OEM Oil Filter: ACDelco PF63
• Aftermarket Filters: Fram XG10575, Wix 57045, Mobil 1 M1-113A

For the 6.6L Duramax Diesel V8 (L5P):

• Oil Capacity: 10.0 quarts (9.5 L) with filter
• Recommended Weight: 15W-40 (or 5W-40 for extreme cold climates below 0°F)
• Oil Specification: API CK-4 (DexosD approved where applicable)
• OEM Oil Filter: ACDelco PF26
• Aftermarket Filters: Fram XG9100, Wix 57202, Mobil 1 M1-303a

Capacity by engine option

Oil change interval

Your Sierra 2500HD is equipped with GM’s Oil Life Monitoring System (OLMS), which calculates oil degradation based on engine operating conditions. However, here are the baseline rules I recommend to my customers:

• Normal Duty: Up to 7,500 – 10,000 miles, or whenever the OLMS indicates, but never exceeding 12 months.
• Severe Duty (Towing, idling, dusty environments): 5,000 miles or 6 months. Heavy-duty trucks are meant to work, and if you are hauling heavy loads or idling on job sites, strictly follow the severe duty interval.

Drain plug torque

• Drain Plug Torque: 18 lb-ft (25 Nm) for both the 6.6L Gas and the 6.6L Duramax.
• Crush Washer Note: The drain plug relies on a rubber O-ring or sealing washer. Inspect it during every oil change. If the rubber is flattened, cracked, or missing, replace the drain plug or the seal. Never over-torque the plug to compensate for a bad seal, as this can easily strip the oil pan threads.

How to change the oil

1. Prepare the truck: Park on a level surface. Ensure the engine is warm (but not dangerously hot) to allow the oil to drain quickly and suspend contaminants.
2. Drain the oil: Remove the oil fill cap up top to allow venting. Place a large catch pan (minimum 12-quart capacity for the diesel) under the oil pan. Remove the drain plug and let the oil drain completely.
3. Replace the filter: Locate the oil filter. Use a proper oil filter wrench to remove it. Ensure the old rubber gasket comes off with the old filter. Prime the new filter (especially important on the 10-quart Duramax) with a bit of fresh oil, lubricate the new rubber gasket, and install it hand-tight (usually 3/4 to 1 full turn after gasket contact).
4. Reinstall drain plug: Reinstall the drain plug with a good seal and torque it to 18 lb-ft.
5. Refill and check: Fill the engine with the specified capacity. Start the engine, let it idle for 30 seconds, and check for leaks underneath. Shut it off, wait 3-5 minutes, and verify the oil level on the dipstick.
6. Reset the Oil Life Monitor: Navigate your driver information center menus to reset the oil life percentage to 100%.

Common issues / tips

For the 2020 generation, pay special attention to the diesel engine's fuel filters. While doing the oil change, it is a great time to check the status of your fuel filter life on the dashboard. The L5P Duramax is incredibly reliable, but it demands clean oil and clean fuel to keep the variable vane turbo and high-pressure fuel system happy.

Additionally, the L8T gas engine requires a full 8 quarts. Don't fall into the trap of putting in 6 quarts like older GM small blocks. Check the dipstick—running 2 quarts low under load can cause catastrophic bearing damage.

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