How Does DEF Work & Why is Purity So Important?

DEF (diesel exhaust fluid) helps control pollution from diesel-burning engines that are equipped with SCR (selective catalytic reduction) systems by neutralizing their nitrous oxide (NOx) emissions. When injected into a diesel vehicle's exhaust stream, DEF breaks down harmful NOx into nitrogen and water — harmless chemicals that pose no environmental or health risks.

However, DEF only works properly if it's pure and uncontaminated. Using contaminated DEF can cause reduced engine performance, SCR  system malfunctions, and potential engine damage - which leads to massive repair bills and vehicle downtime. With purity being so important, PEAK recently upgraded our DEF formulation to include enhanced, triple-filtered purity protection. We think the results make PEAK BlueDEF the best DEF fluid on the market.

Let's dive in and find out why.

DEF basics

Our ultimate guide to diesel exhaust fluid explains everything you need to know about DEF in full detail, but here's a quick cheat sheet with some fundamentals:

• DEF is a mixture of deionized water (67.5%) and high-purity urea (32.5%). It works with your diesel engine's SCR system to neutralize NOx emissions.
   
• NOx emissions from diesel engines vary widely among vehicle makes and models, but they're generally far higher than those produced by regular gasoline-powered engines.
   
• Environmental, health, and safety experts widely consider NOx to rank among the most harmful types of emissions caused by fossil fuels.
   
• In 2010, the Environmental Protection Agency (EPA) adopted the Diesel Emissions Reduction Act, which made SCR systems mandatory in diesel vehicles.

DEF became essential under the Diesel Emissions Reduction Act, and newly manufactured diesel vehicles will shut down without it.

Why DEF purity is so important

Purity is the single most important thing to look for in diesel exhaust fluid, since even small levels of contamination can seriously damage a diesel engine.

Here's what can happen:

• Contaminants can clog your engine's fuel injectors, leading to noticeable losses in power, efficiency, and overall engine performance.
   
• Blockages can build up in your fuel system, making it difficult or impossible to start your vehicle.
   
• DEF's urea components can infiltrate your fuel system, causing corrosion and possibly leading to premature engine failure.
   
• Deposits can collect in your vehicle's SCR system and damage it — possibly beyond repair.

Smoky, soot-filled emissions can also billow out of your vehicle, causing pollution and possibly attracting the attention of traffic enforcement. If an inspection determines that your vehicle is noncompliant with the Diesel Emissions Reduction Act, you or your employer could face hefty fines.

Best practices for handling and using DEF

When it comes to handling diesel exhaust fluid, good habits lead to good results. Following these best practices will help prevent your DEF from becoming contaminated:

Use dedicated equipment

Make sure all funnels, spouts, pumps, hoses, and tools you use when handling diesel exhaust fluid are specially made for DEF. Never use equipment or tools that have been exposed to other fluids or compounds, as this can easily lead to cross contamination.

Keep things clean

Before adding fluid to your DEF tank, make sure the tank and any connected pumps, hoses, or nozzles are clean. If you notice any grease, grime, or dirt, remove it and wipe affected surfaces down with purified water before proceeding.

Never mix DEF with other fluids

Do not mix DEF with diesel fuel or any other fluids. Watch out when fueling up: in some diesel vehicles, the DEF and diesel fuel tanks are located close to each other and you might accidentally put fuel into your DEF tank if you're not careful.

Store your DEF properly

Always keep your DEF in its original container. Transferring it to other containers carries a high risk of introducing contaminants. Avoid exposing your diesel exhaust fluid to direct sunlight, which can degrade the urea in your DEF.

Consult your DEF packaging for manufacturer-specific guidelines but as a general rule, try to store your DEF in temperatures ranging from about 15 to 77 degrees Fahrenheit (-9 to 25 degrees Celsius).

What to do if your DEF is contaminated

If you think your DEF packaging or the fluid inside it has become contaminated, stop using it immediately. Take it to your nearest environmental waste or hazardous materials recycling center for safe disposal.

You'll have a more complicated issue on your hands if the DEF inside your vehicle has become contaminated, but it's essential to take the right action. Otherwise, you could end up with much bigger problems.

Here's what to do:

• Do not start the engine.
   
• Drain the DEF tank. If you don't feel comfortable doing this yourself, have a professional do it for you. Since you shouldn't start your engine if your vehicle contains contaminated DEF, you may need to have your vehicle towed to a service center.
   
• Flush the DEF tank and all connected lines and hoses with deionized water or fresh, uncontaminated DEF.
   
• Replace any filters in your vehicle's DEF tank and connected systems.
   
• Refill your drained, flushed, and cleaned DEF tank with fresh diesel exhaust fluid.

It also wouldn't be a bad idea to have a technician give your vehicle a once-over to make sure the contaminated fluid didn't cause any damage.

BlueDEF's triple-filtered difference

BlueDEF's new and improved triple-filtered formulation delivers the purest diesel exhaust fluid money can buy. Right now, PEAK is the only manufacturer on the market to use this unique triple-filtering process.

The process begins with rigorous water treatments that destroy any and all contaminants in our DEF's deionized water components. In the second step, we subject the urea that goes in our DEF to an equally intensive purification process. Then, after we've mixed the purified water and urea to create our DEF, we put that combined solution through yet another purification treatment.

By the time we're through, there isn't a single contaminant to be found in BlueDEF. We double-check with diligent lab tests before greenlighting a batch for packaging.

Protecting BlueDEF's purity with smart packaging

Our commitment to DEF purity doesn't stop with triple filtering. Improper handling can easily lead to DEF contamination, so we've also engineered our product packaging to help prevent purity problems before they start.

DEF gets poured into a dedicated reservoir, which usually holds about 5 gallons of fluid. Your intuition might tell you to use a funnel to prevent it from spilling when you pour, but this creates a contamination risk. If the funnel has any dust, debris, or residues on it, those impurities will get mixed into the fluid.

Every container of triple-filtered BlueDEF includes a specially sterilized pouring spout, which also goes through careful anti-contamination treatments and checks. By using the spout as directed, you'll avoid exposing your diesel exhaust fluid to ambient impurities.

BlueDEF is as pure as it gets — we guarantee it

PEAK's high-performance BlueDEF line includes two triple-filtered products: our economical base formulation, and premium BlueDEF Platinum with added inhibitors to prevent harmful deposits from building up in your SCR system.

Both BlueDEF formulations are backed by a generous purity guarantee. If your vehicle suffers damage due to DEF contamination and the problem originated with the fluid that came from one of our jugs, we'll help you cover your repair costs.

To learn more about our industry-leading line of diesel exhaust fluid, watch this BlueDEF instructional video.