Freightliner Century 112/120 Fuel Tanks

Frequently Asked Questions About Freightliner Century 112/120 Fuel Tanks

What size fuel tanks fit the Freightliner Century 112 and 120, and how do I know which one I need?

The Century 112 and 120 typically accommodate fuel tanks ranging from 60 to 150 gallons, with 100-gallon and 120-gallon tanks being the most common. To determine the right size, check your frame rail spacing (usually 34" for Century models) and measure the available mounting space between your cab and rear axles. Your existing tank brackets will indicate whether you need a 23" or 25" diameter tank. Always verify your specific truck's configuration, as custom wheelbases may affect tank fitment.

Are aftermarket fuel tanks compatible with my Century's original mounting brackets and straps?

Most quality aftermarket fuel tanks are designed to work with OEM mounting hardware for 1996-2007 Century models. However, you should verify that your replacement tank matches your original's diameter (23" or 25") and mounting style (strap-mount or bracket-mount). Some aftermarket tanks may require new straps if your originals are worn or if you're upgrading to a different capacity. We recommend inspecting your existing brackets for wear and replacing them if they show signs of fatigue or corrosion.

What's the difference between aluminum and steel fuel tanks, and which is better for my Century?

Aluminum tanks are lighter (reducing overall vehicle weight by 50-100 lbs per tank), resist corrosion better, and typically last 15-20 years. Steel tanks are more affordable upfront but are heavier and prone to rust, especially in regions using road salt. For Century 112/120 models used in long-haul applications, aluminum tanks often provide better value despite the higher initial cost. Steel tanks work well for local operations where weight isn't critical and budgets are tight.

Can I install a larger capacity fuel tank than what came stock on my Century?

Yes, you can often upgrade to a larger capacity tank if you have adequate frame space. Many Century 112/120 owners upgrade from 100-gallon to 120-gallon or 150-gallon tanks for extended range. Before upgrading, measure the distance between your cab and drive axles, check for interference with exhaust components or air lines, and ensure your fuel tank straps can accommodate the larger diameter. Some states have regulations on maximum fuel capacity, so verify local DOT requirements.

What additional parts do I need when replacing fuel tanks on my Century truck?

Beyond the tank itself, you'll typically need new rubber mounting bushings, fuel tank straps (if worn or wrong size), sending unit gasket, and fuel line fittings. Many installers also replace the fuel cap, vent lines, and pickup tube assembly during tank replacement. If switching from steel to aluminum or changing tank sizes, you may need different mounting brackets. Budget 2-4 hours for installation, or 4-6 hours if replacing both tanks and associated hardware.