Freightliner Cascadia Fuel Tank Capacity: How Many Gallons Does It Hold?
Quick answer: There's no single fuel capacity for a Freightliner Cascadia. It depends on the tanks the truck was spec'd with, and whether it runs one tank or two. Replacement tanks listed for the Cascadia run from 80 to 150 gallons each. As a real example, a 2020 Cascadia 126 day cab in Penske's lease fleet is spec'd with dual 25-inch aluminum tanks holding 160 gallons total.
Why There's No One Number
Fuel tanks are part of a truck's spec, like the engine, sleeper and axles. Two Cascadias from the same model year can leave the factory with different tank sizes and a different number of tanks. That's why searches for a "2023 Cascadia fuel tank capacity" or "2026 Cascadia fuel tank capacity" don't have a clean answer. The year doesn't set the capacity. The build does.
Cascadia Fuel Tank Sizes
Aftermarket replacement tanks listed for the Freightliner Cascadia 113 and 125 come in these sizes. Tanks are named by diameter and length in inches:
Capacity (per tank) | Diameter x length listed |
80 gallons | 23 x 48 in, or 25 x 38.5 in |
90 gallons | 25 x 46.5 in |
100 gallons | 25 x 50 in |
110 gallons | 23 x 60 in |
120 gallons | 23 x 71.5 in, or 25 x 60 in |
140 gallons | 23 x 84 in, or 25 x 70.5 in |
150 gallons | 23 x 88.75 in, or 25 x 74.5 in |
Sizes are from the BESTfit aluminum tank listings at 4 State Trucks. Some of those tanks are also listed for other Freightliner models. For a current 116 or 126, confirm the fitment for the specific truck before ordering.
A Real Example: 2020 Cascadia 126 Day Cab
Penske's spec sheet for a 2020 Freightliner Cascadia 126 tandem-axle day cab lists:
Fuel: dual 25-inch aluminum tanks, 160 gallons total
DEF: 13-gallon tank
Engine: Detroit DD13, 435 HP
Transmission: Detroit DT12 automated
Wheelbase: 178 inches
That's one truck, not a rule, but it shows how capacity reads on a real spec sheet: tank count, diameter, material and the total.
How Capacity Adds Up
Dual tanks: add the two together. Two 100-gallon tanks give you 200 gallons.
Weight: diesel is roughly 7 pounds per gallon, so 200 gallons adds about 1,400 pounds. If you run close to the weight limit, that counts. Our guide to how much a semi truck weighs shows how fuel fits into your payload math.
Range: multiply the gallons you actually carry by your truck's real fuel economy. Use your own numbers from your routes and loads, not a brochure figure.
How to Find the Fuel Capacity of a Used Cascadia
Get the spec sheet. It should list tank count, size and total capacity. Ask the dealer for it.
Measure the tanks. Diameter and length together tell you the size. Match them against tank listings like the ones above.
Look for a label. Check each tank for a manufacturer label or tag.
Inspect while you're there. Look at the straps, brackets and mounting, and check for dents or leaks around the tank and fittings.
Don't count the DEF tank. It's separate and holds diesel exhaust fluid, not fuel.
Looking at one of our trucks? Call us and we'll tell you exactly how it's spec'd, tanks included. You can see what's on the lot now on our inventory page, and if you're comparing Cascadia models, start with Cascadia 116 vs 126.
Cascadia Fuel Tank Capacity: Common Questions
How many gallons does a Freightliner Cascadia hold?
There's no single number. Fuel capacity depends on the tanks the truck was spec'd with. Replacement tanks listed for the Cascadia run from 80 to 150 gallons each, and many trucks carry two. One real example: a 2020 Cascadia 126 day cab in Penske's lease fleet is spec'd with dual 25-inch aluminum tanks holding 160 gallons total.
Does the model year change a Cascadia's fuel tank capacity?
Not on its own. A 2020, 2023 or 2026 Cascadia can each be built with different tank sizes. Capacity comes from how that specific truck was spec'd, so check the truck, not the year.
Does a Freightliner Cascadia have two fuel tanks?
Many do, but not all. The tank setup is chosen when the truck is spec'd. If a truck has two tanks, its capacity is the two tank sizes added together.
What size fuel tanks fit a Freightliner Cascadia?
Aftermarket tanks listed for the Cascadia 113 and 125 come in 80, 90, 100, 110, 120, 140 and 150 gallon sizes, in 23-inch and 25-inch diameters. Tanks are sized by diameter and length, so measure before you order.
How much does a full tank of diesel add to a truck's weight?
Diesel weighs roughly 7 pounds per gallon, so 160 gallons adds about 1,120 pounds and 200 gallons adds about 1,400 pounds.
Is the DEF tank part of the fuel capacity?
No. DEF has its own separate tank. The Penske Cascadia example above lists a 13-gallon DEF tank alongside its 160 gallons of fuel.
Talk to All American Truck Sales
With 35+ years in the trucking industry, we help owner-operators and fleets find the right truck for the work, not just the one on the lot. If you don't see what you need, we'll use our extensive network to find the right truck for you.
Phone: 563-587-8844
Visit: 3186 Hughes Ct, Dubuque, IA 52003
Inventory: aatrucksales.com/shop
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