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How big is the gas tank on a 2500HD diesel?

The Duramax-powered 2500HD typically uses a 36-gallon fuel tank (about 136 liters).


In practice, capacity can vary by model year, cab/bed configuration, and optional equipment. This article explains typical sizes and how to verify the exact figure for your truck.


Typical capacity and what affects it


Most current-generation 2500HD diesel trucks use a 36-gallon main tank. However, fuel capacity is not identical across all years and configurations; some cab/bed setups or production changes can alter the tank size slightly.



    Factors that influence tank size include:


  • Model year and generation: Tank capacity has generally been around 36 gallons for Duramax-powered 2500HDs, but changes across generations can occur.

  • Cab and bed configuration: Regular, extended, or crew cab variants with different bed lengths can affect packaging and potentially tank size.

  • Drivetrain and trim: 2WD vs. 4WD and certain trims may be paired with different optional equipment that can influence usable capacity.

  • Auxiliary tanks or regional options: Some configurations may include an auxiliary tank or alternative fuel systems that change total usable capacity.


For the exact figure on your specific truck, consult the official documentation or the dealer. The precise capacity is listed on the vehicle’s window sticker and in the owner's manual for the model year.


How to verify the exact capacity for your vehicle


To confirm the precise capacity for your 2500HD diesel, check these sources:



  • Window sticker (Monroney label) on the driver’s door jamb that lists fuel capacity.

  • Owner’s manual for your model year and configuration.

  • GM official spec sheets or the dealership’s service department with your VIN.


If you’re planning long trips or trying to estimate range, verifying the exact tank size for your VIN is the safest approach.


By generation and year


Current generation (2020s)


In the current Silverado/Sierra 2500HD with Duramax diesel, the standard fuel tank is typically 36 gallons.


Earlier generations


Older 2500HD models varied in capacity, generally falling in the low to mid-30s of gallons depending on configuration.


Summary


For the Chevrolet Silverado / GMC Sierra 2500HD with a Duramax diesel, the standard fuel tank is typically 36 gallons (about 136 liters). Exact capacity can differ by year, cab/bed configuration, and optional equipment. Always refer to the window sticker or the owner’s manual, or consult a GM dealer, to confirm the precise capacity for your specific truck.

Kevin's Auto

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.