Best Def Fluid For Cummins

Last Updated:
Best Def Fluid For Cummins

Diesel engine technology has gotten much cleaner in contemporary times, and if you have a vehicle with a diesel engine made after 2010, you’ll likely need a suitable diesel exhaust fluid to break down and reduce emissions, in compliance with environmental protection agency standards. Today, we have selected and reviewed some of the best diesel exhaust fluids you can buy for your diesel vehicle.

Top 5 Best Def Fluid For Cummins

Last update on 2021-12-05 at 05:01 / Affiliate links / Images from Amazon Product Advertising API

1. AD BLUE Diesel Emissions Fluid

The AdBlue Diesel Emissions Fluid is approved for Porsche, Audi, BMW, Volkswagen, and other vehicles that need emissions fluid. The fluid comes in four 0.5-liter bottles that all feature spill-proof nozzles. The unique nozzle design makes it easy to pour the fluid, and the top portion of the bottles comes with positive stops to further reduce the likelihood of the content spilling.

Although it is not the cheapest diesel emission fluid you can get on the market today, it is a high-quality product that will help you achieve better fuel economy and increased engine power.

User-friendly bottle

One of the major highlights of the ADBLUE Diesel Emissions Fluid, in addition to the high quality of the formulation, is the bottle design. It is easy to pour, and the design discourages fluid dripping and overfilling.

Reduce emissions significantly

Suppose your vehicle is a 2010 or newer model with a diesel engine. In that case, you’re most likely going to need a diesel exhaust fluid like this one to break down the dangerous nitrogen oxide emission into nitrogen and oxygen and improve the overall vehicle performance.


  • It is easy to pour
  • High-quality formulation
  • High compatibility


  • Relatively expensive

2. Valvoline Premium Blue Diesel Exhaust Fluid

This Valvoline exhaust fluid is one of the best options for Cummin diesel engines. As a premium quality fluid, it reduces the nitrogen oxide level in engines to almost zero, thus providing optimal protection for both the vehicle and the environment.

Another exciting factor is that it is compatible with all on and off-highway Selective Catalytic Reduction systems. The API and AdBlue certification should allay whatever concerns you have about the quality of this product.

Low consumption rate

Diesel exhaust fluids are generally pricey, so choosing a fluid with a low consumption rate goes a long way in keeping the maintenance cost for your diesel vehicle minimal. The Valvoline Premium Blue Diesel Exhaust Fluid is formulated for a long-lasting effect.

Contaminant free

The only thing worse than buying an ineffective DEF is buying one that’ll further contaminate your diesel engine. At manufacturing, the Valvoline Premium Blue goes through high-quality checks to ensure that the formulation is pure and free from contaminants that can damage your engine.


  • Easy to pour
  • High-performance fluid
  • Works for a wide variety of engine types


  • A little pricey

3. Ford Genuine PM-27-GAL Diesel Exhaust Fluid

If you own a Cummins or Duramax diesel engine, the Ford Motorcraft DEF is needed to break down and reduce the nitrogen oxide to protect the engine and the environment. The formulation makes use of a Selective Catalytic Reduction catalyst to reduce nitrogen oxide emissions in diesel vehicles.

Also, we love that the fluid meets the requirements and purity standards of DIN70070 and ISO 22241. Pouring the fluid in the diesel exhaust fluid tank can be tricky – that’s the one thing we don’t like about this exhaust fluid. Nonetheless, you can buy a separate nozzle to ease this process.

Heavy duty application

This was specifically designed for heavyweight Ford trucks that do intensive hauling, but it is also compatible with many other big vehicle engines.

Environmentally friendly

One of the reasons you have to use DEF in your engine is to reduce the toxic effect of the exhaust on the environment. The Ford Motorcraft Diesel Exhaust Fluid is very effective in breaking down nitrogen oxide emissions into harmless oxygen and nitrogen elements.


  • Low consumption
  • Perfect for heavy-duty engines
  • Reduces harmful emission


  • It doesn’t come with a nozzle

4. Blue Def DEF002-2PK Diesel Exhaust Fluid

Like the other exhaust fluids on our list, the Peak BlueDef Diesel Exhaust Fluid is not a fuel additive. Instead, it is injected into the exhaust stream to convert nitrogen oxide into water vapor and nitrogen gas that is harmless to the engine and the environment.

The formulation comprises around 70% water and about 30% pure urea, so it is stable and contains no contaminants that can damage your vehicle engine. With all its exciting features, the Peak BlueDef Diesel Exhaust Fluid is still one of the more affordable options.

No contaminant

This exhaust fluid is formulated with high-quality urea and deionized water with zero impurities. The  Peak Blue Def Diesel Exhaust Fluid ensures a higher level of emission system protection.

Brings down emissions

While all DEFs have the primary function of reducing emissions in diesel engines, this particular formulation features high-grade urea to make it one of the most reliable and best DEF fluids for Duramax engines.


  • It is reasonably priced
  • Low consumption
  • Meets all requirements


  • Not easy to pour into tank

5. Prestone HD1001 Command Diesel Exhaust Fluid

The Prestone HD1001 Command  Diesel Exhaust Fluid is one of the more affordable fluids on our list. However, its affordability does not take anything away from its quality and functionality. The non-toxic solution has a 67.5% water content and a 32.5% urea content.

Like the other formulations we have reviewed, it is formulated to be compatible with all SCR-equipped diesel engines. Although it is a versatile diesel exhaust fluid compatible with many diesel engines, we recommend it as the best DEF fluid for Cummins engines.

Easy to handle

One of the things you want to look out for when buying a DEF is a container that’s easy to handle and pour. Thankfully, the Prestone HD1001 Command  Diesel Exhaust Fluid container has an ergonomic handle that’s very easy to hold and pour with.

Low consumption

What makes the Prestone HD1001 even more valuable is that it has a low consumption rate. It lasts considerably longer than cheaper and lower-quality exhaust fluids, so you can be sure that you’re getting a good return for your money spent.


  • Low consumption
  • Pure urea
  • Compatible with a variety of engines


  • Does not come with a nozzle

What is diesel exhaust fluid?

Diesel Exhaust Fluid (DEF)  is a harmless chemical substance composed of deionized water and urea. DEF is totally harmless, and it was introduced to reduce air pollution caused by combustion.

How do you select a diesel exhaust fluid?

Selecting a diesel exhaust fluid requires some level of observation basically because of the high number of fake ones on the market. When selecting a diesel exhaust fluid, ensure it has a urea concentration of 32.5%  by weight and not just a urea solution.

Why do diesel engines need diesel exhaust fluid?

Without diesel exhaust fluid, your diesel engine will not be able to run properly. This means the power would be drastically reduced. Also, in burning fuel to release energy, diesel engines release some toxic emissions that can increase fuel consumption. So, diesel exhaust fluid helps break down the toxic emissions into non-toxic substances like nitrogen and water. And as we know, nitrogen forms a part of the air we breathe in, so it’s safe. With this, air pollution from diesel engines is reduced.

How does diesel exhaust fluid work?

Diesel exhaust fluid works in a vehicle equipped with SCR- meaning SELECTIVE CATALYST REDUCTION. During combustion, the exhaust gas from your engine is filtered to trap all the ash and soot generated from burning. Then the exhaust gas goes into a nozzle. In the course of traveling past the nozzle, the projecting spout sprays some diesel exhaust fluid into the exhaust system.

The exhaust gas mixed with diesel exhaust fluid then goes into the catalytic converter, where the chemical reaction begins. Diesel exhaust fluid is made from pure urea (the type found in the urine, but this time, a pretty pure form) and deionized water. So, when this pure urea meets with the exhaust gas, a reaction takes place, and they both convert nitrogen dioxide and monoxide into harmless nitrogen and water.

Is diesel engine fluid bad for diesel engines?

No, diesel engine fluid is not bad for diesel engines. In fact, your vehicle needs diesel engine fluid just as much as it needs diesel fuel. Now, this is not to say that your vehicle would power with only diesel exhaust fluid, but this fluid is needed to increase horsepower, protect your engine from wearing out quickly and save the earth.

How long does diesel exhaust fluid last?

This substance is capable of lasting longer than you think. Diesel exhaust fluid lasts longer in cold temperatures than it would in warmer temperatures. It lasts up to 2 years when stored under a temperature between 12 degrees to 86 degrees Fahrenheit. But when exposed to sunlight or warmer temperatures, its shell life could be compromised.

In usage, diesel exhaust fluid is not like your diesel fuel that might need a top-up every now and then; you can refill the diesel exhaust fluid every time you change your oil. When you have a full tank of DEF, it could last up to 6300 miles.

What happens if you run out of diesel exhaust fluid?

Well, the efficiency of your engine is reduced until you have a refill. But then, this is a question of ‘if’ because it is close to being ‘impossible’ as you would always receive various warnings before the diesel exhaust fluid finishes completely.

What happens if you put fuel or diesel exhaust fluid in the wrong tank?

Have it in mind that diesel exhaust fluid is not to be mixed with fuel, but in case you dumped diesel exhaust fluid in the fuel tank, or vice versa, ensure you do not turn on your engine. All you need to do is to quickly drain the fuel or DEF while the machine is in its original position. Starting the engine or shaking the machine could make the fuel of DEF spread to the wrong places, thereby damaging the SCR catalyst or the diesel engine.

Is there a difference in diesel exhaust fluid brand?

Not much difference. Only ensure the brand you are buying follows the ISO 22241 standards, having a urea concentration of 32.5% by weight. 


What year did diesel exhaust fluid start?

In 2010, the Environmental Protection Agency (EPA) introduced the use of diesel exhaust fluid. But before this time, this concept had been used in agriculture and industrial power generation.

Does my equipment use a DEF filter?

All equipment using DEG should have a DEF filter which is located in the doser pump. The doser pump is directly behind the DEF tank.

What happens if DEF freezes?

Nothing much. The diesel exhaust fluid would usually freeze on extremely cold days. This would neither affect the quality of the DEF nor damage the engine. When you start your engine, the DEF thaws as it gets heated.

What happens if my equipment runs out of DEF?

When your machine runs out of DEF, the engine’s power reduces and slows down progress. But for machines that are not built to run out of DEF, the machine might stop working until there is a refill.

Where is DEF fluid injected?

DEF is injected into the exhaust stream of the diesel engine.

Is DEF fluid made from pig urine?

No, DEF is synthetically made, which makes it totally harmless.

Can Diesel Exhaust Fluid Freeze?

Absolutely yes! And the good news is that its quality would not be affected when frozen.

Who Needs Diesel Exhaust Fluid?

If you have vehicles or any other equipment ranging from slightly heavy to very heavy, you sure need a diesel exhaust fluid.


A diesel exhaust fluid should break down the harmful nitrogen oxide produced in a diesel engine into benign water vapor and nitrogen gas. If your vehicle has a diesel exhaust fluid tank, you need one of these formulations for your engine to run smoothly. DEFs can be quite expensive, but we have included some relatively affordable options on our list.

Leave a Comment