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Nov 8, 2018 - 10 minute read

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Best DEF Fluid In 2022: Guide For Cummins, Duramax, Powerstroke

Best DEF Fluid
(Last Updated On: February 3, 2021)


Diesel technology and the engines themselves have witnessed a substantial rise in clean operations within the last several years.

This increase can be directly attributed to the 2010 EPA regulations. Modern diesel engines deliver better fuel economy with a more rugged design.

Numerous industries across the globe, have benefited from improved diesel designs and cleaner operations.

Best def fluids for different trucks

Best def fluids for different trucks

The EPA regulations of 2010 forced diesel technology to improve. This directive resulted in manufactures supplying better low-sulfur fuels and specialized converters to curtail the toxic nitrous oxide exhaust fumes.

A significant improvement in diesel technology was the addition of DEF. DPF is a fluid that can be poured into a special tank and is then injected into the exhaust pipeline to reduce emissions.

When combined with the exhaust fumes, it transforms the toxic nitrous oxide into ammonia and carbon dioxide which are two manageable gases.

In this article, we are going to breakdown the best DEF fluid for different popular diesel engines on the market. Let’s get started!

1. Best DEF Fluids: Most Pure

Peak Commercial and Industrial Products began business in 1973 at the peak of a petrochemical shortage.

The company boasts of full bulk distribution facilities. From drum storage to an extensive distribution network. BlueDEF is on everyone’s radar when it comes to choosing the right solution.

BlueDEF conforms to the ISO 22241 standard and is API certified. BlueDEF uses synthetic urea with the lowest of impurities along with deionized water.

Pros Cons
Customers with different auto types recommend BlueDEF. Some customers reported BlueDEF tripped a check engine light on their vehicle.
Good price at all retail outlets. Container seals could be better.

2. Best DEF Fluids: Most Versatile

Prestone is synonymous with quality automotive products. The company has been in business since 1927 and is an iconic American brand.

Their DEF conforms to all governmental regulations for purity. Operators can expect to see the Prestone brand of products at every truck stop and automotive shop across the globe.

Prestone DEF is compatible with all modern SCR systems. The company estimates operators will need one gallon of DEF to every 50 to 75 gallons of fuel.

Pros Cons
Worldwide brand May not be suitable for all diesel engines and could trip an engine code.
Cheap DEF at truck stops, about $2 a gallon

3. Best DEF Fluid for Duramax Engines

ACDelco offers a complete line of automotive parts and fluids. The company is a fully owned subsidiary of General Motors.

The Duramax line recommends using only ACDelco DEF for their engines. This GM DEF is specifically made for Duramax engines.

The ACDelco DEF meets every stringent guideline for purity. DEF will need to be refilled approximately every 1000 miles of use.

Pros Cons
ACDelco has a long history of OEM part manufacturing for General Motors May be a little pricey if purchased in 1 Gallon increments
Compatible with any GM brand

4. Best DEF Fluid for a Cummins

Sinopec is a leading distributor for many Diesel motor products from hydraulic oil to engine grease in bulk.

Sinopec DEF is designed for cars, trucks, and heavy equipment. This DEF meets the ISO 22241 standard for urea purity.

Designed to satisfy the stringent demands of modern SCR systems.

Pros Cons
DEF can be utilized for a variety of other vehicles. Compatible with any GM brand
Some customers report check engine lights after adding this DEF.

Another alternative is the Fleetguard AdBlue DEF by Cummins Filtration Products. Fleetguard DEF is the only DEF endorsed by Cummins Diesel. However, it is not easily available to buy.

5. Best DEF Fluid for Ford PowerStroke

Motorcraft is a decade’s long partner of Ford Motor Company. Motorcraft has a comprehensive line of automotive products produced with Ford in mind.

This AUS32 fluid satisfies the stipulations of ISO 22241, DIN70071 for purity. Motorcraft DEF is formulated to work for any Ford Diesel engine and many competitors.

Pros Cons
Motorcraft DEF will not generate any vehicle warranty issues. Shop around for the best price
Original OEM product Packaging and seals could be better

What To Look For In DEF Fluids?

Are All DEF Fluid Brands The Same?

All DEF is not created equal. Any fluid claiming to be DEF must meet quality specifications set by the ISO (International Organization for Standardization). First, DEF must have a urea concentration of 32.5%.

This proportion was singled out because it has the lowest freezing point. Impurities are precisely defined and extremely low, for the reliable operation of the SCR system.

By definition, if the DEF does not comply with the ISO standard, the material cannot be called DEF.

Counterfeit solutions claiming to be DEF flood the market. Using these unlicensed products can severely damage the SCR system.

Consequences Of Using Poor DEF 

DEF that does not comply with the ISO standard can seriously damage a diesel engine and the SCR operation.

Diesel failures can show up in a few days, weeks or months. The purity of the urea used in DEF must be pharmaceutical grade. Agriculture grade urea will contain excessive aldehydes, biuret, and other impurities.

DEF not using deionized water will cause SCR failures. NON-deionized water contains zinc, magnesium, iron, chromium and other hazardous substances.

How To Use DEF

Diesel Exhaust Fluid is a non-toxic, non-corrosive substance and harmless to deal with. DEF is the least hazardous of all the fluids needed in a diesel truck.

However, DEF is caustic to some metals such as aluminum, copper, and zinc. ISO 22241 supplies a list of recommended storage containers.

DEF is transferred into a tank on the truck by a spouted container. Consumers can buy DEF in quantities from 1 Gallon to hundreds of gallons and bulk.

Veteran operators will invest in a large capacity transfer tank, rather than carrying several smaller amounts. Any spillage should be cleaned away at once with a cloth. If the DEF dries, it will crystalize and still can be wiped away.

From a dedicated diesel exhaust fluid tank aboard the vehicle, the fluid is sprayed into the exhaust by a metering system.

The injection flow is between 2% and 6% of diesel consumption. The meter ensures longer refill times.

Operators living in frigid climates have extra steps. DEF has a freezing point of 12°F for the Selective Catalytic Reduction (SCR ) system to operate correctly, a part of the DEF must be thawed before an operation.

EPA regulations require there be full DEF flow within 70 minutes of engine start-up. To comply with statutes, operators will install specialized tank heaters to help regulate the DEF temperature.

Further details can be found in our Guide to Diesel Exhaust Fluid (DEF).

Benefits of Using Diesel Exhaust Fluid (DEF)

Many people will tell you DEF fluid is harmful to your vehicle but the fact is using DEF is a great way to help protect our environment from harmful emissions. Lets look at some of the benefits of DE

  • It is non-toxic. In comparison to other vehicle fluids like diesel fuel or brake oil, DEF fluid it’s by far less hazardous. In fact, many DEF fuel brands use naturally occurring substances that are biodegradable.
  • Won’t freeze so our friends up North need not worry
  • Wont vaporize easily
  • Better fuel mileage and increased power
  • Better performance from your DPF which leads to fewer regeneration
  • Compliance with proper regulations - EPA, ISO & API certified
  • Reduced maintenance and reducing wear and tear on the engine.

This fluid is importing in reducing emission gasses since these harmful substances (NOx for example) are one of the main causes of acid rain and increasing greenhouse gasses which leads to smog and worsened global warming.

Key Takeaways

When choosing the best DEF fluid for your diesel engine, make sure to pick the right product. Not picking the right fluid can cause damage to your engine which can turn out to be even more costly in the long run.