Frequently Asked Questions About Freightliner Cascadia 113/125 Diesel Fuel Tanks

What size fuel tanks are available for the Cascadia 113/125, and which configuration is best for my needs?

The most common fuel tank sizes for Cascadia 113/125 models range from 80 to 150 gallons per tank. Single tank configurations typically use 100-150 gallon tanks, while dual tank setups commonly feature 80-120 gallon tanks on each side. For regional haul applications, a single 120-gallon tank often provides sufficient range. Long-haul drivers typically prefer dual 100-120 gallon tanks for extended range and better weight distribution. Consider your typical route distances, payload requirements, and whether you need the flexibility of dual tanks for weight balance when hauling varying loads.

Will these fuel tanks fit my specific Cascadia model year, and what are the mounting differences?

Fuel tanks for Cascadia 113/125 models are generally compatible across 2008-2017 model years, but mounting brackets and strap configurations can vary. The 2008-2012 models use a different strap mounting system than 2013-2017 models. Additionally, day cab and sleeper cab configurations may have different tank positioning requirements. Always verify your specific VIN and cab configuration before ordering. Tanks designed for the newer 2018+ Cascadia models (often called "New Cascadia") will NOT fit the 113/125 series due to completely different frame rail designs and mounting systems.

What material options are available, and how do aluminum and steel tanks compare for durability?

Both aluminum and steel fuel tanks are available for Cascadia 113/125 models. Aluminum tanks are 40-50% lighter than steel equivalents, improving fuel economy and payload capacity. They resist corrosion better in salt-heavy environments but can develop stress cracks around mounting points after 5-7 years of heavy use. Steel tanks are more impact-resistant and typically last longer in rough conditions but are prone to rust, especially along the bottom seams and strap contact points. Most over-the-road drivers prefer aluminum for weight savings, while vocational and construction applications often choose steel for durability.

What installation challenges should I expect, and can I install these myself?

Installing a fuel tank requires disconnecting fuel lines, electrical connections for sending units, and potentially relocating DEF tanks or battery boxes. The tank itself weighs 40-80 pounds empty, but removal of old tanks full of fuel requires proper draining equipment. Critical challenges include ensuring proper ground strap connection, correctly torquing mounting straps (typically 45-55 ft-lbs), and verifying fuel line routing to prevent kinks. While experienced mechanics can complete installation in 2-3 hours per tank, first-time installers should budget 4-6 hours and have a helper available. Professional installation is recommended if you're unfamiliar with fuel system safety procedures.

Are aftermarket fuel tanks DOT approved, and will they affect my warranty or inspection compliance?

Quality aftermarket fuel tanks from reputable manufacturers are DOT approved and stamped with proper certification markings. Look for tanks that meet FMVSS 301 standards and display the manufacturer's DOT certification number. Using DOT-approved aftermarket tanks will not void your vehicle warranty, though improper installation might affect warranty coverage for fuel system components. For inspection compliance, ensure tanks have intact certification labels, proper venting, and rollover protection valves. Some states have additional requirements for tank modifications, so verify local regulations if you're changing tank size or configuration from OEM specifications.