How big is a Class C gas tank?
There isn’t a single standard size for a Class C motorhome’s fuel tank. The vehicle’s fuel capacity varies by chassis and engine, while the onboard propane tanks used for appliances follow common RV configurations. In practice, Class C gas-powered rigs typically carry about 25–60 gallons of fuel, and propane systems commonly rely on two 20-pound cylinders, with larger options available on some models.
What determines the size of the fuel tank
The size of a Class C’s fuel tank is shaped by the chassis, drivetrain, and the goal of the build (range vs. payload). Manufacturers optimize for weight, storage space, and towing needs, which means different models have different capacities even within the same class.
Fuel tank sizes by common Class C chassis
Here’s a snapshot of typical ranges you’ll encounter across popular chassis platforms. Note that exact numbers can vary by year, trim, and aftermarket modifications.
- Ford E-Series / E-450 (gasoline): commonly around 40–60 gallons depending on configuration.
- Chevrolet Express / GMC Savana (gasoline): typically about 31 gallons, with some heavy‑duty conversions pushing toward 40 gallons.
- Mercedes‑Benz Sprinter (diesel or gasoline variants): usually about 24–27 gallons.
- Ram ProMaster (diesel or gasoline variants): around 24 gallons.
Exact capacity should be verified on the vehicle’s spec sheet or the fuel filler door label, as there can be notable variations between model years and floorplans.
Propane tanks in Class C motorhomes
Beyond the fuel tank, RVs rely on propane for cooking, heating, and some refrigeration. Most Class C RVs use a standard propane setup, but configurations vary by model and usage needs.
- Two 20‑pound propane cylinders are the most common setup on many Class C rigs.
- Some models use two 30‑ or 40‑pound cylinders for longer trips or higher appliance usage.
- Propane capacity is stated in pounds; a full 20‑lb cylinder holds about 4.7 gallons of propane (roughly 18 liters).
Check the owner’s manual or the labeling on the propane compartment to know the exact cylinder size and total propane capacity for a given unit.
How tank size affects range and usage
Fuel tank size directly influences driving range, while MPG depends on weight, terrain, and driving style. On average, Class C motorhomes achieve roughly 8–12 miles per gallon, but this varies widely. To estimate range, multiply your expected MPG by your fuel tank size, then add a reserve for hills, headwinds, and quick trips to the pump.
What to check when evaluating a Class C’s tanks
When shopping for a Class C, verify both the vehicle’s fuel tank and propane system specs. Look for:
- Tank capacity labels on the fuel filler door or inside the owner’s manual.
- Propane cylinder type and total propane capacity (and ensure proper regulator and leak checks).
- Age and condition of cylinders, hoses, and regulators; schedule servicing as recommended by the manufacturer.
- Diagnostic notes in maintenance records about fuel system inspections and propane system tests.
Understanding these specs helps you plan trips, budgets for fuel and propane, and maintenance schedules more accurately.
Summary
In short, a Class C gas tank doesn’t have a universal size. Vehicle fuel capacity usually ranges from about 25 to 60 gallons depending on chassis, while onboard propane systems most often consist of two 20‑pound cylinders (with larger options available). Always verify the exact capacities for a given unit from official specs or labels, and factor tank size into trip planning and fuel/propane budgeting.
