How big is the fuel tank on a 2018 Chevy 2500HD?

The fuel capacity for the 2018 Chevy Silverado 2500HD depends on the chosen powertrain. In short, the gasoline 6.0-liter V8 version uses a 31-gallon tank, while the Duramax 6.6-liter diesel uses a 36-gallon tank. This article explains those figures and how they apply to common configurations.

Tank sizes by engine

Below is a concise breakdown of the factory tank capacities associated with the two primary engine options for the 2018 2500HD. Note that most configurations share the same capacity, but there can be minor variations based on cab/bed setup or optional equipment.

• Gasoline engine: 6.0L V8 — 31-gallon fuel tank


• Diesel engine: Duramax 6.6L — 36-gallon fuel tank

Factory documentation and window stickers are the best sources to confirm the exact capacity for a specific truck, especially if you’re comparing different cab and bed configurations or aftermarket modifications.

How the capacity affects range and daily use

Fuel tank size directly influences potential driving range, but real-world range also depends on engine efficiency, payload, towing, and driving conditions. In practical terms, a 31-gallon tank on a gas 2500HD typically yields a shorter on-the-road range than the 36-gallon diesel variant under similar usage, though miles per gallon and load factors will influence the exact figures.

Notes on configuration and verification

While the two main figures cover the vast majority of 2018 Silverado 2500HD trucks, there are rare exceptions due to specific configurations or production variations. Always verify the exact capacity for a given vehicle via the owner’s manual, the window sticker, or GM’s official specification sheet.

Summary

The 2018 Chevy Silverado 2500HD offers two primary fuel-tank sizes based on the engine choice: 31 gallons for the 6.0L gas V8 and 36 gallons for the Duramax 6.6L diesel. For precise figures, check the specific vehicle’s documentation, as cabin/bed configurations and optional equipment can lead to small variations. This information helps with planning range, fuel stops, and overall ownership expectations.

How big is the fuel tank on a 6.6 Duramax?

A standard 6.6L Duramax fuel tank holds about 36 gallons, but replacement tanks are available with capacities of 52, 56, or 62 gallons. The specific capacity depends on the truck's model year, cab and bed configuration, and whether a standard or aftermarket tank is installed. For example, a 2020-2025 Crew Cab, Short Bed truck often has a stock 36-gallon tank, while aftermarket options can increase this to 56 or 62 gallons, as seen on Vin Specific Enterprises and TITAN Fuel Tanks. 

• Standard fuel tank: Approximately 36 gallons. 
• Aftermarket options:
  • 52 gallons: Available for older models (2001-2010). 
  • 56 gallons: Available for newer models (2020-2025). 
  • 62 gallons: Available for a wide range of models, often for Crew Cab Short Bed configurations. 

What year Chevy Silverado 2500HD to avoid?

Years to avoid for the Chevy Silverado 2500HD include 2003–2006, which had issues with brake lines, ABS, and electrical components. Additionally, the 2014–2015 models are also problematic due to high recall numbers, transmission complaints, and AC problems, along with potential transmission failures in some 2017 and 2018 models. 
This video discusses the best and worst years of the Chevy Silverado: 59sCar Lensy YouTube · Sep 11, 2025
Early 2000s models

• 2003–2006: These years are notorious for safety concerns related to their brake systems, especially brake line corrosion. They also experienced frequent issues with the anti-lock braking system (ABS) and malfunctioning instrument clusters. 

Third-generation models (2014–2019) 

• 2014–2015: Despite being a new generation, these models had a high number of recalls and were plagued by transmission complaints, electrical faults, and air conditioning problems. 
• 2017: This year is specifically mentioned for transmission issues. 
• 2019: This model year had several reported issues, particularly in the early stages, and the 6.2L V8 engine faced a safety probe for potential engine failures in 2019–2024 models. 

Specific engine and component issues

• Duramax LML engines (2011–2016): These are prone to CP4 fuel pump failures, and it is recommended to replace the pump to prevent damage, notes Hot Shot's Secret. 
• Duramax LLY engines (2004.5–2005): Known to overheat, so proper cooling and airflow are essential, says Hot Shot's Secret. 
• Transmission problems: Beyond the specific years mentioned, some models from 2014 to 2019 on the 1500 series had issues with the factory tune causing premature wear and potential failure, according to Reddit users. 

This video discusses the top 5 problems in the third generation of the Chevy Silverado 2500 truck: 59sCar ExpertlyYouTube · Jun 4, 2025

What size fuel tank does a Chevy 2500 HD have?

36.0 gal
Fuel & MPG
0/0 mi. 36.0 gal.

What is the fuel tank capacity of a 2018 Silverado 2500?

The 2018 Silverado 2500HD has a 36-gallon fuel tank capacity. This capacity applies to both gasoline and diesel models and is consistent across different cab and bed configurations.
 

• Fuel tank size: 36 gallons 
• Compatibility: This size applies to both gasoline and diesel versions of the 2018 2500HD model. 
• Fuel type: The tank is compatible with flex-fuel (unleaded/E85) in the gasoline models.