What’s The Best DEF (Diesel Exhaust Fluid) For Ford F250?

Diesel trucks are powerful vehicles that are perfect for towing or other strenuous jobs. These trucks need additional products to ensure that fewer pollutants are released when the fuel burns. There are many diesel exhaust fluids on the market. The number of options can make picking one product difficult. For owners of the Ford Super Duty F250, look no further! We've done the research and can tell you what DEF product is best for you!

You should use Motorcraft brand diesel exhaust fluid for your Ford F-250 and other Ford diesel engine vehicles. Motorcraft is owned and operated by Ford, so Ford dealers and mechanics highly recommend this brand. However, you can use any DEF fluid that complies with ISO 22241 standards and is certified by the American Petroleum Institute.

Now that you know what fluid you should use, let's learn more! Keep reading to discover how to fill your DEF tank and what happens if you accidentally mix diesel with the diesel exhaust fluid!

closed fuel cap with Diesel text marking and diesel exhaust fluid beside it colored blue. What's The Best DEF (Diesel Exhaust Fluid) For Ford F250

Ford Super Duty F250

If you want a rugged vehicle, you probably want a Ford Super Duty. This series of cars has won best-in-class in multiple categories, including conventional towing and payload capacity.

JD Power also rates the 2021 F250 at an 84 out of 100 for Quality and Reliability. That means you shouldn't experience very many defects or design flaws.

The 2021 and 2022 F250 models have a Power Stroke V8 Turbo Diesel. Models for both years also have a variety of trims to choose from, with costs ranging from $34,000 to $86,000.

What's The Best DEF (Diesel Exhaust Fluid) For Ford F250

What is DEF?

Diesel exhaust fluid, or DEF, is a liquid solution made with 32.5% carbamide (also known as urea) and 67.5% deionized water.

Carbamide is a naturally occurring compound that is found in the urine of mammals. The carbamide found in DEF isn't made from urine. It is synthetically made.

Before using any DEF solution on your vehicle, ensure your vehicle has an SCR (selective catalytic reduction system).

As of 2010, all diesel engines manufactured must meet the lowered nitrogen oxide standards. This updated regulation means that all heavy-duty engine makers, except two, are using an SCR. Navistar International and Caterpillar are the two companies that don't use SCR.

DEF Shelf Life

Before adding DEF to your vehicle, check your container for a manufacturing date. The dates are usually stamped somewhere on a product's container or box.

The exact location will vary depending on what brand you use. Knowing the manufacturing date is vital because DEF can go bad.

DEF is best stored at a constant temperature between 68 degrees Fahrenheit and 23 degrees Fahrenheit. At these temperatures, the product should have a three-year shelf life. Ford never recommends keeping or using DEF if it's older than three years.

How to use DEF

DEF is filled via a fill port, very similar to the port for fuel. You can find the DEF fill area next to the fuel port. If it isn't there, you may also find it under the hood.

It's important not to combine DEF and diesel. The fill ports are designed differently and are different colors to avoid mistakes. However, it's important to double-check before filling up with either DEF or fuel.

After locating the area, you'll put DEF, determine how you're going to refill the DEF tank. You can fill it up at a gas station or truck stop, just like you would with fuel.

In this instance, you'll pay with cash or card and then fill your DEF tank. The pump will automatically stop once your tank is filled.

You also have the option of using a container. You can find different DEF products in many retail stores and online. In these cases, you'll also need a funnel or nozzle to help you transfer the liquid.

Once your tank is full, the liquid should automatically stop if you're using a nozzle. If you're using a funnel, slowly fill your tank and stop periodically to check your levels to avoid overfilling manually.

Read the instructions that come with your diesel exhaust fluid for the best information for adding DEF to your tank!

Check out this Motorcraft brand spout on Amazon.

Best DEF Products

There are a variety of manufacturers that create DEF products. Choosing a brand that will work with your vehicle isn't expired and complies with ISO 22241 standards is essential.

Many brands will post how they're compliant with the labeling to make finding good DEF easier for the consumer.


The only brand that Ford recommends for their diesel exhaust fluid needs is Motorcraft. Ford launched this auto parts brand in 1972.

The best part of using Motorcraft with your Ford F250 is peace of mind. Ford created Motorcraft DEF with their cars in mind. 

Check out this Motorcraft brand DEF on Amazon.

Peak Blue Def

Peak Blue Def exhaust fluid is a well-known and popular choice. It is manufactured by Old World Industries, which is the number one supplier of antifreeze with coolant, diesel exhaust fluid, and automotive headlights.

Check out this Peak Blue DEF on Amazon.


Valvoline is a well-established and trusted brand. This product meets all ISO 22241 and API standards. 

Check out this Valvoline Premium Blue DEF on Amazon.


Prestone has been providing consumers with auto parts and supplies since 1927. They offer a wide range of high-quality products, including diesel exhaust fluid.

Prestone DEF meets ISO, API, and EPA standards, which means it's safe for humans and animals. The price point on this product does tend to be higher than other brands.

Check out this Prestone brand DEF on Amazon.

How much blue DEF does an F250 hold?

The 2021 Ford F250 can hold 7.4 gallons of diesel exhaust fluid. Ford recommends using Motorcraft Diesel Exhaust fluid instead of other brands or alternative exhaust fluids.

However, Ford also notes that API's diesel exhaust fluid, American Petroleum Institue, certified and meets ISO 22241 standards will work for their vehicles.

How often do you have to add DEF?

How often you need to add DEF will vary based on how often you drive your vehicle and the quality of DEF that you're using.

You'll typically use two to three percent of diesel exhaust fluid for every gallon of diesel that's burned. You should expect to refill your DEF tank after the third time filling up with fuel.

What happens if you run out of DEF?

Vehicles are required to have alerts warning you when you're running low on DEF. For Ford vehicles, if you use contaminated fluid or run out, you won't run your car. You will force the engine to work at a limited capacity.

You'll be unable to reach average speeds. If you continue to drive without DEF, your F250 will switch to engine idle only mode. Once it comes to this point, you will be forced to refill your DEF tank before operating the car.

What is a substitute for DEF?

If you're in a pinch and have no other option, you can use distilled water instead of diesel exhaust fluid. It isn't recommended, and there is a chance that it could cause damage to your vehicle.

It is never recommended to urinate into the diesel exhaust fluid tank. Yes, urea, a key component in DEF, is found in urine, but that doesn't mean you can use them interchangeably.

Position to add fuel and to add Diesel Exhaust fluid to the passenger car

What happens if you put diesel in the DEF tank?

Putting diesel in your DEF tank can cause severe damage to the SCR system. If you notice your mistake before you start your vehicle, you should be able to drain your DEF tank.

It is still possible that flushing your tank will work even if you have already started the car. It's best to speak to a professional mechanic to be sure.

Accidentally putting the wrong product in either the fuel or diesel exhaust fluid tank can cause significant damage to your truck.

Exhaust pipe on pickup truck car close up. What's The Best DEF (Diesel Exhaust Fluid) For Ford F250

In Closing

If you're driving a diesel, one of the most important things you should learn is which type of exhaust fluid you should be using. While Ford recommends only using Motorcraft, many great products also meet the ISO's high-quality standards.

Always make sure to double-check the product you've selected meets those requirements and is also certified by the American Petroleum Institute.

You may also enjoy:

Should I Buy A Diesel Car? [Pros And Cons]

Can You Convert An F250 To An F350? [Pros, Cons, And How To]

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