Will meet all of the specifications and standards you need to give your Selective Catalytic Reduction diesel engine a high level of NOx exhaust reduction. Includes a fill hose that works well for pouring the product into the DEF tank successfully.
Even though it ships with two 2.5-gallon bottles, it has a high price per gallon.
Successfully creates safe nitrogen gas and water vapor from NOx in diesel exhaust. This product meets all EPA regulations regarding Selective Catalytic Reduction engines. Gives you a good value versus other DEF options. Ships with a fill tube so you can add the product to the DEF tank safely.
Jug may leak if fill tube is not attached properly, so you may want a funnel.
Works as advertised to help maintain Selective Catalytic Reduction diesel engines. Contains all of the certifications required for a product like this. Nicely designed container means you don't have to worry about leaks. Trusted brand.
A little more expensive than some other DEF products in this bottle size.
Made especially for Ford diesel-powered vehicles. Meets all required standards for treating NOx emissions in heavy duty diesel engines. Selective Catalytic Reduction approved. Nozzle is designed to reduce messes and spills during application.
Some quality control issues reported including broken seals and missing nozzles. Pricey.
Works with Selective Catalytic Reduction systems of General Motors vehicles including heavy duty vans and trucks. Reduces NOx emissions. Compatible with older models dating back to 2010. Made by a brand that is trusted by General Motors owners.
Costly, especially considering you only get one gallon for the price.
We recommend these products based on an intensive research process that's designed to cut through the noise and find the top products in this space. Guided by experts, we spend hours looking into the factors that matter, to bring you these selections.
If you’re new to vehicles that run on diesel fuel, you’ll soon discover they’re quite a bit different from standard gasoline-powered vehicles, beyond the difference in fuels. For example, you might need to change the oil and fuel filters more frequently. Because a diesel engine burns fuel at a higher temperature, you might have to use an exterior heating system in the wintertime. But the most obvious difference is that you need to add diesel exhaust fluid to a separate tank on the diesel vehicle to remove harmful emissions and enable it to run properly.
Purchasing the best digital exhaust fluid for your situation depends on a few criteria. At BestReviews, we can help you better understand the differences among diesel exhaust fluids, so you can find the best one for your vehicle.
Our shopping guide gives you plenty of helpful information about diesel exhaust fluids, so you can make sure your diesel vehicle runs properly.
Unless you have experience with diesel vehicles, you might not know much about diesel exhaust fluid (DEF). This bright blue liquid is a mixture of roughly two-thirds deionized water and one-third urea. The color helps you distinguish it from gasoline or diesel fuel.
You add DEF to your vehicle as needed. It goes into a separate tank than the diesel fuel and runs through the selective catalytic reduction (SCR) system. Diesel vehicles emit dangerous nitrogen oxide (NOx). DEF breaks down the NOx emissions into nitrogen and oxygen, elements commonly found in air.
The DEF you use must meet ISO 22241, which is an international standard that determines the quality of the product.
If you have a 2010 or newer model vehicle that runs on diesel fuel, it almost certainly needs DEF. A vehicle that needs DEF is designed so that it won’t operate properly without DEF in the tank.
If you’re unsure whether your vehicle requires diesel exhaust fluid, look for a special DEF tank. This tank is near but separate from the diesel fuel tank. DEF and diesel fuel should never mix.
Because diesel exhaust fluid is an expensive add-on, and because it can be a hassle to keep on hand, it might be tempting to run the diesel vehicle without filling the DEF tank. However, the vehicle manufacturer is required to design the vehicle so you can’t.
The Environmental Protection Agency (EPA) sets the rules that vehicle manufacturers must follow regarding the use of DEF. Under these rules, dashboard messages and warning lights warn the driver when the DEF tank is running low on fluid.
An empty DEF tank limits the vehicle's performance to speeds of up to five miles per hour until the tank is refilled.
Let’s just say you don’t want to put the wrong fluid in the wrong tank! It will result in a significant repair expense for you. Be very careful when adding either diesel fuel or DEF to your truck.
Diesel fuel in DEF tank: There are safeguards built into the system to prevent you from putting diesel fuel into the DEF tank. The diesel fuel nozzle is larger in diameter than the entry hole of the DEF tank, ensuring that you can’t accidentally fill the DEF tank with diesel fuel using the nozzle at a gas station. Also, the DEF tank often has a bright blue cap that will help you avoid placing diesel fuel in this tank.
However, if you’re inadvertently put diesel fuel in the DEF tank, you need to have the system repaired immediately. Even a tiny amount of diesel fuel could significantly damage the system that uses DEF.
It can be frustrating to pick the right DEF for your vehicle. All diesel exhaust fluid must have a urea concentration of 32.5%, so how different can the brands be?
Impurities: To meet EPA standards, DEF must contain a limited percentage of impurities such as iron, zinc, and aluminum. These impurities can enter the DEF if the manufacturer uses poor-quality deionized water, for example. Too many impurities in the DEF could cause the SCR system to fail prematurely. A cheaper brand of DEF might be at the edges of the impurity limits, while a more expensive DEF might have many fewer impurities than required by the EPA.
Urea: An approved brand of DEF must use pharmaceutical-grade urea rather than agricultural-grade urea, which might have impurities like biuret in higher levels than higher-quality urea.
EPA standards: To call itself diesel exhaust fluid, the product must meet all EPA standards, especially ISO 22241. If you find a cheap product that claims to be diesel exhaust fluid, but it doesn’t meet ISO 22241 standards, don’t purchase it. Such a fluid could damage your vehicle’s SCR system.
The prices for DEF aren’t set in stone and fluctuate over time depending on market conditions, supply and demand, your location, and the size of the container. You can expect to pay between $2.50 and $8 per gallon for DEF.
You can expect to pay between $4 and $8 per gallon for containers of this size.
When you buy more, you can expect to pay a little less, between $3 and $5.50 per gallon.
Commercial operations will pay prices similar to that of diesel fuel, between $2.50 and $4 per gallon, for large quantities of DEF.
A. Technically, diesel exhaust fluid is not an additive because it isn’t mixed with the diesel fuel. Instead, the DEF is poured into a separate tank on your diesel fuel vehicle. The SCR system built into the vehicle then applies the DEF to the exhaust system as needed to eliminate NOx emissions.
A. The use of diesel exhaust fluid in a selective catalytic reduction system has only occurred in the last several years. If you’ve always driven older trucks, you haven’t had to use DEF because your trucks don’t have an SCR system. This system began appearing on diesel vehicles with the 2010 model year.
A. If your vehicle uses diesel fuel and has an SCR system, you need DEF. Among vehicles commonly aimed at consumers, pickup trucks and some sport utility vehicles (SUV) run on diesel fuel, although large sedans occasionally use diesel, too. A vehicle with an SCR system has a special tank for the diesel exhaust fluid. This DEF tank, separate from the diesel fuel tank, is usually distinguished by a bright blue cap.
A. The system uses chemical reactions between the diesel exhaust fluid and the vehicle’s exhaust to reduce harmful emissions. The SCR system uses an injection system to deliver the diesel exhaust fluid into the vehicle’s exhaust system. The DEF is then converted into ammonia by the SCR system. Once the ammonia is mixed with the NOx emissions, it breaks them down into safe emissions of nitrogen and oxygen.