Frequently Asked Questions About Freightliner FL70-FL80 Diesel Fuel Tanks

What years and models are these fuel tanks compatible with?

Our Freightliner FL70-FL80 diesel fuel tanks are designed to fit models from 1995 through 2007. However, compatibility can vary based on your specific truck configuration, engine type, and wheelbase. FL70 models typically use 50-80 gallon tanks, while FL80 models often accommodate 80-150 gallon tanks. We recommend checking your VIN or existing tank measurements before ordering, as some chassis modifications may affect fitment.

Are these fuel tanks made of aluminum or steel, and which is better for my application?

We offer both aluminum and steel fuel tanks for FL70-FL80 models. Aluminum tanks are lighter (reducing overall vehicle weight by 50-70 pounds), resist corrosion better, and are ideal for trucks operating in humid or salt-prone environments. Steel tanks are more affordable, extremely durable against impacts, and better suited for heavy-duty applications or rough terrain. Most owner-operators prefer aluminum for long-haul applications, while vocational fleets often choose steel for durability.

What mounting hardware and accessories do I need for installation?

A complete fuel tank installation requires tank straps, mounting brackets, rubber isolators, and typically new fuel line connections. Most FL70-FL80 tanks use 2-inch wide straps with J-bolts or T-bolts depending on your frame rail configuration. You'll also need a sending unit (if not included), fuel cap, and potentially new crossover lines for dual tank setups. We recommend replacing rubber grommets and bushings during installation to prevent premature wear from vibration.

How difficult is it to install these tanks, and what are common installation challenges?

Installation typically takes 2-4 hours per tank for experienced mechanics. Common challenges include: aligning new tanks with existing fuel lines (especially on trucks with aftermarket modifications), removing corroded mounting hardware from old tanks, and ensuring proper ground connections for sending units. Step-mounted tanks require additional care to maintain proper clearance. Many customers report that having a second person helps significantly when positioning larger capacity tanks.

What capacity options are available, and how do I choose the right size?

We stock fuel tanks ranging from 50 to 150 gallons for FL70-FL80 trucks. The right size depends on your application and frame rail space. Standard behind-cab mounting typically accommodates 50-100 gallon tanks, while extended frames can handle up to 150 gallons. Consider your typical route distances, payload requirements, and whether you're running single or dual tanks. Remember that larger tanks add weight (approximately 8 pounds per gallon of diesel) and may require upgraded mounting straps.