45 Gallon Extended Range Fuel Tank for 2019-2026 Mercedes Sprinter 144" & 170"

Plan on 5 to 7 hours with a lift or a good floor jack and a helper. The tank is long and awkward rather than heavy (45 lb dry), and the job is mostly careful disconnecting and reconnecting of stock parts. The full manufacturer instructions with photos for every step are linked below.

Before you start

• Disconnect and isolate both negative battery cables, and don't work on a hot underbody.
• Check for the lateral crossmember behind the stock tank. If your van doesn't have it, this tank won't mount.
• Look for anything mounted under the floor within about 24" of the rear of the stock tank: water tanks, plumbing, heater lines, or bolts from your interior build. The new tank extends farther forward and rearward than stock.
• Have a bucket ready. Up to a gallon of fuel is trapped in the filler neck and drains out when you loosen the filler hose.

Where installs go wrong

• Don't skip the float swap. The kit includes a longer float for your OE sending unit. Without it, the gauge can't read the extra capacity. After installing it, check that the float barely touches the tank floor.
• Check float clearance before the tank goes up. Pull the 5 bolts on the main vent and look inside with a flashlight (or take a photo) to confirm the float is clear of the venturi tube. If they touch, the gauge sticks and eventually drops to empty and stays there.
• Zip tie the new vent hose behind the filler plate. If the 5/16" hose at the filler door isn't secured to the back of the metal plate, it interferes with the plastic filler door.
• Don't pinch the vent hose on the way up. Push the 5/16" hose onto the T fitting before the tank is fully raised and watch it as you lift.
• Plus nuts take two people. One person holds the tool with a 7/8" wrench while the other runs the bolt with a 17mm socket until the plus nut fully collapses. The kit includes a spare plus nut in case one doesn't set.

Finish checklist

Make sure every strap bolt is tight, confirm driveshaft clearance, tug-test the fuel line connections, double-check the vent and fill lines, then fill the tank completely and look for leaks. If your van has an auxiliary fuel tap for a diesel heater, reconnect it and note that it will now stop pulling fuel at about 1/3 to 1/2 tank.

How to Choose an Extended Range Fuel Tank for Your Sprinter

A bigger fuel tank is one of the most useful upgrades for a Sprinter that travels, and one of the easiest to get wrong. The tanks look similar in photos, but fitment is specific to model year and body style, and what's already bolted under your van matters as much as the tank itself. Here are the questions we get most, in order, with a rule for each one you can check on your own van.

1. Which tank fits your Sprinter?

Sprinter fuel tanks are specific to the chassis generation. The 2007-2018 Sprinter (NCV3) and the 2019+ Sprinter (VS30) use different tanks, and they don't cross over. Within each generation, body style decides the rest.

• 2019-2026 diesel, 144" or 170": 45 gallon tank
• 2007-2018 diesel, standard 144" or 170": 47 gallon tank
• 2007-2018 diesel, 170" crew van, 144" dually, or 2018-2019 Winnebago Revel: 40 gallon tank
• 2019+ crew van or dually: a shorter 40 gallon tank exists for these vans. Reach out and we'll order it.

How to choose: find the model year on the label in the driver door jamb, then look at your body style. If you have a crew van, a dually, or a 144" NCV3 with a ride height sensor on the rear axle, you're in the smaller tank.

2. Will your fuel gauge and range readout be right?

This is the question behind most returns. With these tanks the gauge stays on full for the first 5 to 7 gallons, then moves normally, but only if the van has the Mercedes J51 fuel gauge option. Separately, the van keeps calculating fuel from the stock 24 gallons, so it counts down to empty and thinks it's out of fuel while the tank is still close to half full.

On 2019-2026 vans, the Fuel Capacity Recalibration Module is a must with any bigger tank: it updates the van to the new capacity (40, 45, or 47 gallons) and adds J51 if needed. On 2007-2018 vans there's no module, so confirm J51 with your Mercedes dealer and plan to use the trip meter for range.

How to choose: on a 2019+ van, order the module with the tank, whether or not you have J51. On a 2007-2018 van, call your Mercedes dealer with your VIN and ask if the van has J51.

3. What's already under your van?

A bigger tank has to go somewhere, and it goes forward and rearward of the stock tank. That's where many builds put fresh water tanks, plumbing runs, heater fuel lines, and floor bolts from seat rails and cabinets. Here's how far each tank extends past the stock footprint:

• 45 gallon (2019+): needs about 24" clear behind the rear of the stock tank (or 19" behind the large rear crossmember), and doesn't stick out farther toward the driver side than stock
• 47 gallon (2007-2018): 2.4" forward and 32.5" rearward
• 40 gallon (2007-2018): 13.1" forward and 3.3" rearward

The 45 and 47 gallon tanks also need the lateral crossmember behind the stock tank for the added rear strap. Planning undercarriage water storage too? We carry a 22 gallon driver side undercarriage water tank and a 16 gallon passenger side undercarriage water tank. Reach out and we'll help you confirm the layout before you order both.

How to choose: get under the van with a tape measure. Measure back from the rear edge of the stock tank and note anything within that distance. If something's there and can't move, choose the shorter tank.

4. How much range will you actually gain?

Multiply capacity by the mpg you actually get. Using 20 mpg as an example:

• Stock 24 gallons: about 480 miles
• 40 gallons: about 800 miles (+320)
• 45 gallons: about 900 miles (+420)
• 47 gallons: about 940 miles (+460)

A loaded camper with a roof rack and all-terrain tires often runs closer to 15 to 18 mpg, so run your own number. At 16 mpg, a 45 gallon tank is about 720 miles versus 384 stock.

How to choose: take the longest stretch you regularly drive between reliable fuel stops (for us, that's usually somewhere in Baja) and pick the tank that covers it with at least a quarter tank to spare.

5. Weight and payload

Diesel weighs roughly 7 lb per gallon. Over the stock 24 gallons, a full 40 gallon tank adds about 112 lb of fuel, a 45 adds about 147 lb, and a 47 adds about 161 lb, plus the tank itself (37 to 45 lb dry). RV owners on forums flag this often, because many factory campers leave the line close to their gross vehicle weight rating.

How to choose: weigh your van loaded for a trip at a truck scale and compare it to the GVWR on the door jamb label. If you have less margin than the extra fuel weight, choose a smaller tank or trim weight elsewhere.

6. Construction and warranty

Replacement tanks are either molded plastic or fabricated metal. Our tanks are 1/4" cross-linked polyethylene, which won't rust, and they carry a lifetime manufacturer warranty. Fabricated aluminum tanks for the Sprinter exist, but they're mostly imports that cost more than twice as much and often ship freight only.

How to choose: look for a stated wall thickness, a real warranty, and a design that reuses your OE sending unit and fuel lines so there's nothing new to wire.

7. Replacement tank or auxiliary tank?

Some owners consider adding a separate auxiliary tank that transfers fuel into the stock tank. The catch is overfilling: gravity-feed and electronic transfer systems can push the main tank past full, which closes the rollover valves early and removes the vapor space the tank needs. That can pressurize the tank and cause leaks, and it voids the warranty on these tanks. A single larger tank avoids all of that.

How to choose: if you want more range from one fill point, go with a replacement tank and don't pair it with a transfer tank.

8. Diesel heater and the auxiliary fuel tap

If you run a diesel heater off the Sprinter's auxiliary fuel tap, it reconnects to the new tank. On a stock tank the aux tap stops drawing at about 1/4 tank. With these tanks it stops at about 1/3 to 1/2 tank, so the heater always leaves you a bigger reserve for driving.

9. DIY or shop install?

All three tanks are stock-location replacements that reuse the OE sending unit, but the jobs differ. The 45 gallon includes a float swap and plus nuts (no drilling). The 47 gallon adds plus nuts and a filler pipe cut. The 40 gallon is the simplest, using the stock strap bolts with a filler pipe cut. Expect 4 to 7 hours with a lift or floor jack and a helper, or have our San Diego shop install it.

Before you order: checklist

• Model year and generation confirmed (2007-2018 or 2019+)
• Diesel engine (these tanks are diesel only)
• Body style checked: crew van, dually, or rear-axle ride height sensor
• Lateral crossmember behind the stock tank (45 and 47 gallon)
• Clear space measured behind and in front of the stock tank
• J51 fuel gauge option confirmed with your dealer
• 2019+ van: Recalibration Module in your cart (required)
• No auxiliary transfer tank in the system
• Loaded weight checked against GVWR

How the 45 gallon tank lines up

• Fitment: 2019-2026 diesel VS30, 144" and 170", including listed 4x4 Storyteller, Winnebago, and Pleasure-Way builds
• Gauge and range: requires the Recalibration Module so the van reads the full 45 gallons instead of thinking it's empty early
• Clearance: no farther toward the driver side than stock; needs about 24" clear behind the stock tank
• Range: about 900 miles at 20 mpg
• Construction: 1/4" cross-linked polyethylene, lifetime warranty
• Install: stock location, reuses the OE sending unit with a longer float, no drilling