To meet EPA pollution rules, most new diesel trucks are fitted with selective catalytic reduction (SCR) systems that utilise diesel exhaust fuel (DEF).
What is a SCR system?
A catalyst reacts with engine exhaust to break down ecologically hazardous exhaust components in the SCR system. Injector nozzles, in a nutshell, spray controlled dosages of DEF into the exhaust. The DEF vaporizes and decomposes into ammonia and carbon dioxide, which mix with the nitrogen oxide in the exhaust to produce the harmless nitrogen and water byproducts.
First of All
DEF fluid is only for vehicles with the SCR system, therefore don’t try to use it on an earlier truck. Although this may seem self-evident, uninformed owners and even well-intentioned service station attendants and technicians at non-diesel shops have mistakenly assumed that because DEF is so wonderful for new diesel trucks, it must also be good for older diesel trucks.
Despite the fact that measures have been put in place to keep diesel fuel separate from DEF, it still happens: DEF is placed into the diesel tank by accident, or diesel is poured into the DEF tank by accident. When this happens, it’s more than a little annoyance: it can result in major damage and pricey repairs.
A fill port, a tank, and lines from the tank to the SCR and injection nozzles make up the DEF system. The dispensers should be properly labeled, and the DEF tank’s fill port, which has a blue cap, is designed to be smaller than the diesel tank’s fill port, preventing the diesel nozzle from being inserted into the DEF tank’s fill port.
Non-DEF chemicals are detected by SCR systems, which include built-in warnings. If non-DEF enters the SCR catalyst, the driver will receive a warning and a code indicating approaching SCR interruption.
What Happens If I Put Diesel into a DEF Tank?
Because diesel is lighter than DEF, it will float on top of it. If it gets inside the SCR catalyst, it can cause substantial damage, necessitating service or, worse, a (expensive) catalyst replacement. Before replenishing the DEF tank, it should be drained and thoroughly cleaned with deionized water. A single teaspoon of a foreign contaminant can contaminate a full tanker load of DEF.
What Happens If I Put DEF into a Diesel Tank?
You remove the fuel cap and open the fuel filler door, and your brain goes into automatic mode.
Putting DEF in the diesel tank is a simple error that could result in a truck being towed to the junkyard.
Because DEF is made up of urea and water, the entire tank of fuel becomes contaminated right away. Long-term implications will ensue if the engine is started and the diesel and DEF combination is introduced into the engine.
The DEF fluid crystallizes once the engine is started, causing irreversible damage… and the repair might cost as much as $12,000.
DEF corrodes and damages a variety of metals, including carbon steel, brass, aluminum, copper magnesium-nickel, and zinc.
What happens when you put DEF in a diesel engine?
DEF (Diesel Exhaust Fluid) is a non-hazardous mixture of 32.5 percent urea and 67.5 percent deionized water. DEF is sprayed into diesel vehicles’ exhaust streams to break down harmful NOx emissions into harmless nitrogen and water. Selective Catalytic Reduction (SCR) is a system that can be found on 2010 and later model year vehicles, as well as many diesel pickups and SUVs. DEF isn’t a gasoline additive, and it’s never mixed with diesel. It’s kept in its own tank, usually with a blue filler cap.
Does DEF ruin diesel engines?
The Clean Air Act of 1970 paved the way for the creation of the Environmental Protection Agency. The Environmental Protection Agency (EPA) has been constantly evolving and enacting laws to address the country’s environmental requirements for 46 years. For many years, owners of three-quarter and one-ton light-duty pickup trucks were not required to install additional smog equipment. All of that changed in 2008, when the Environmental Protection Agency mandated the use of diesel particulate filters on all three-quarter-ton and larger vehicles, as well as biannual smog testing that included a visual assessment of the truck to ensure the DPF parts were still there. The rules were tightened even more in 2010.
Many people believed that the age of enormous power and torque was finished, and they resolved to never buy another vehicle. However, something fantastic occurred, as well as the polar opposite. Americans have proven to be adaptable and resilient. Every manufacturer worked out a way to reduce NOx emissions while still producing more horsepower and torque than ever before. Strife yields bread, and bread yields innovation.
The application of selective catalytic reduction was the engineering breakthrough. To break down the created NOx into harmless nitrogen and water molecules, the great majority of these systems use diesel exhaust fluid (a mixture of urea and deionized water) injected into the exhaust system. Since the introduction of DEF (Diesel Exhaust Fluid), also known as after-treatment technology, in the exhaust, the manufacturer is free to create as much power as they like. The DEF is kept in a separate tank that is insulated and heated, with a blue filler cap to identify it.
Despite the effort around technology breakthroughs, there are still two factions of diesel guys out there: those who have accepted the EPA modifications and those who are still adamantly opposed to any limits. There has been a transition to older used diesel engines or remanufactured diesel engines that have been grandfathered in for individuals who are unable to accept the modifications. The purpose of this essay is to lay forth the cold hard facts concerning DEF and to educate the public on how to make better diesel operator decisions.
What exactly is Diesel Exhaust Fluid (DEF)?
DEF is a mixture of 67.5 percent deionized water and 32.5 percent urea from a chemical standpoint. Urea is a nitrogen chemical that, when heated, converts to ammonia and is employed in a range of industries. Although urea is technically produced from a urine waste, it is synthesized for mass manufacture. The American Petroleum Institute regulates most DEF products. Let’s look at the science of DEF in combination with exhaust. DEF is made up of two parts: (NH2)2CO and (NH2)2CO. When injected into hot exhaust gas, the water evaporates, leaving ammonia and isocyanic acid.
STEP 2: With water, the isocyanic acid breaks down chemically into carbon dioxide and ammonia:
STEP 3: At this step in the chemical reaction, ammonia will decrease nitrogen oxides in the presence of oxygen and a catalyst:
2(NH2)2CO + 4NO + O2 = 4N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2 = 7/2N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2 = 7/2N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2 = 7/2N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2
How Often Do You Need To Fill Up the DEF Tank?
This is a question that is specifically dependent on the diesel truck’s MPG and usage. The usual average light duty truck will require 2-3 gallons of DEF per 800 miles, regardless of the load, according to the OE manufacturer. Most new trucks with an average miles per gallon rating of 20+mpg, on the other hand, will travel 8,000-10,000 miles on a tank full of DPF (10 gallons). Each vehicle is different; for example, a Dodge Ram has a gauge that shows how much DEF is left in the tank, while a GM truck has a digital readout and a Ford truck has a basic low DEF indicator.
Fuel models for medium and heavy duty trucks will vary, but DEF usage will be around 2% of total fuel consumption, according to Cummins Filtration. One gallon of DEF is used for every 50 gallons of diesel fuel used. Here are some forecasts from our friends at Cummins Filtration for Medium and Heavy Duty Consumption:
Where can you buy DEF?
Don’t be tricked by thinking that DEF can be purchased just about everywhere. DEF is typically sold in large bottles holding numerous gallons of the substance at truck stops. If you’re in a pinch, some petrol stations will have DEF, but don’t bank on it. It is critical to note that if you do not refill an empty DEF tank, the engine will shut down automatically. Because DEF isn’t offered everywhere, you don’t want to be trapped anywhere with an empty tank. TravelCenters of America, Walmart, Target, Love’s Travel Shop, SAPP Brothers, Flying J Truck Stops, Petro Stopping Centers, and Pilot Travel Centers, O’Reilly’s, NAPA, and Advanced Auto are all common places to buy DEF. We’ve also put together a list of the most popular DEF manufacturers.
What are the Pros and Cons of a DEF Truck?
DEF has few drawbacks because it is a relatively straightforward technique. However, because the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) are prone to clogging, they can cause a slew of maintenance and repair concerns. These systems are intricately designed, and even a simple blocked filter can result in pressure and temperature differentials that influence the engine’s overall performance.
The only disadvantages of DEF are the higher initial cost, added weight, and the need for more storage space for an extra gallon of the fluid. Better fuel economy, more horsepower, more optimized combustion, fewer regeneration troubles, less engine wear, and it only emits nitrogen and water vapor into the air are some of the benefits.
Is emissions production really an important issue?
Whether it’s a major concern or not is debatable, given that all light-medium diesel engines built after 2008 must meet with EPA regulations. Smog, greenhouse gas emissions, and acid rain have all been linked to NOx emissions. The DEF converts NOx into pure nitrogen and water vapor as part of the Selective Catalytic Reduction system (SCR). Climate change is a contentious issue, but we can all agree that adding additional gasses to the atmosphere of any kind isn’t something we need.
Will DEF Lower My Fuel Mileage?
It is natural to believe that any EPA-mandated alterations to the diesel engine will be detrimental, but this is not the case. The big diesel makers learned that they could fine-tune the engine in whatever way they wanted, then let the SRC and DEF remove the particles. The engines are designed with performance in mind first, and then the SRC, DPF, and DEF are added as an afterthought to remove what is no longer required. Manufacturers have discovered that engines with SCR technology achieve better fuel mileage than engines with conventional internal pollution reduction systems. Fuel fed to the SCR provides an additional supply of components to burn. It is possible to increase fuel mileage by as much as 5% to 7%.
Has this new DEF Technology Ever Been Used Before?
DEF technology has been employed in agriculture, industry, and large-scale power generation in the country for decades. The premise is the same everywhere: urea combined with heat produces ammonia, which induces a chemical reaction that reduces NOx by 70% to 95%. In fact, nitrogen-released fertilizer accounts for 90% of urea production. It’s worth noting that automotive-grade urea has a far higher purity level than fertilizer-grade urea. If a lower-grade fertilizer, urea, is used in vehicle engines, the SCR may disintegrate, causing the engine to fail. It could even cause ECM sensors to issue an inaccurate DEF Tank Empty signal.
Does DEF Evaporate After A Period of Disuse?
Yes and no are the answers. With the valves wide open, the temperature at which DEF combines with NOx exhaust immediately out of the cylinder head is between 1400-1600 F. The chemical reaction occurs at substantially higher temperatures than those experienced on a hot summer day. For example, converting the DPF to ammonia and evaporating it would take two years at a steady temperature of 125 degrees F. However, because DEF is roughly 2/3 water, any temperature above 86 F risks some evaporation. Unless exposed to consistent hot climes, you won’t have to worry about a gallon or two of the stuff going bad or evaporating from inactivity.
Is DEF a Toxic and Harmful Chemical?
Urea, the active element in DEF, has been chemically produced since 1828, when German chemist Friedrich Wöhler used ammonium chloride to treat silver cyanate. Herman Boerhaave, a Dutch chemist, was the first to detect urea in urine in 1727. Urea is mostly employed in agricultural fertilizers, but it is also found in the chemical industry, explosives, lotions, skin creams, hair removers, plastics, dish washes, and fuel cells. Humans are not extremely poisonous to urea and, as a result, DEF. Urea can irritate the eyes, skin, and respiratory tract, but it is not dangerous. High quantities of urea in the blood can be dangerous to humans, however absorption of modest doses of urea, when accompanied by proper water intake, is not. In nature, urea can induce algal blooms, which can produce harmful fumes when it decomposes over its melting or heating threshold. When nitrites are mixed with certain oxidants, such as chlorides, they can create fires or even explosions.
What happens to the engine if the DEF Tank is empty?
The EPA now requires all diesel engine manufacturers to include a tiered warning system (internal gauges on the dash) that tells the driver how near the DEF tank is to being empty. The truck will stop working if you ignore the DEF warning. Some diesel engine manufacturers allow the engine to go into low-power mode, allowing the truck to “limp home” or limiting the number of times the engine can be turned over. However, the diesel engine would eventually fail to start. Treat the DEF tank as if it were a fuel tank; you don’t want to be stranded somewhere because you forgot to replace it.
Does DEF Have a Low Freeze Point?
At 12 degrees Fahrenheit, the normal 32.5 percent DEF solution begins to crystallize and freeze. When urea and water are combined in DEF, they both freeze at the same time. This is advantageous to the user because the DEF solution does not get diluted or too concentrated as the fluid thaws. The product’s grade is unaffected by freezing and thawing cycles. When DEF is frozen, it expands by 6.5 percent to 7% by volume. Freezing periods are accommodated by the packing.
What is the best method to keep DEF from freezing?
Keeping a gallon or two of DEF in your vehicle is totally safe, but it is not recommended. At 86 degrees Fahrenheit, DEF begins to degrade. It’s all too easy to forget about the DEF in the rear of your vehicle, and given enough hot days, the fluid can become unstable and degrade, but at a very slow rate. A diluted DEF without the 32.5 percent urea combination can be harmful to DEF and SCR, however this is a rare occurrence. As a result, on exceptionally cold days below 12 degrees Fahrenheit, DEF will freeze in the DEF tank. This is totally normal and will have no negative impact on the engine. The SCR systems are intended to give heat to the DEF tank, allowing the tank and related supply lines to thaw quickly.
Can I add anti-freezing solution to the DEF mixture to keep it from freezing?
DEF has a relatively specific formula consisting of 32.5 percent urea and water, but it also contains additional compounds in trace amounts to help stabilize the product. The precise chemical makeup of the mixture would be disrupted by an addition, lowering the NOx reduction characteristics. The DEF mixture’s ability to function effectively will be jeopardized by further blending, and the SCR system will be harmed.
How is the production of DEF regulated and can I make my own?
It is not advisable for direct consumers to make their own DEF. DEF is strictly regulated, has stringent standards for chemical purity, and comprises chemicals that are critical to the SCR system’s operation. DEF must be utilized with SCR systems and meet all ISO norms and API requirements, according to Caterpillar, Cummins, and Detroit Diesel, among others. The American Petroleum Institute (API) has a wholly voluntary program that confirms the chemical purity of DEF and that manufacturers fulfill ISO requirements. API Certification is achieved by all major DEF brands present on the consumer market.
What is the shelf life of DEF?
The batch of DEF will last around two years if it is stored at ambient temperatures of 75 degrees Fahrenheit with no large periods of exposure to heat above 86 degrees Fahrenheit. If a package of DEF is heated for an extended period of time, the fluid will last about a year.
Who are the major manufacturers of DEF Fluid?
DEF Fluid is made by a variety of companies. “Oilmen Truck Tanks,” a website, has collected a list of 13 main manufacturers. DEF is available for $2-$3 per gallon at most big truck stops, auto parts stores, and convenience stores.
How can you determine the age of a container of DEF?
A manufacturers date can be found somewhere on every DEF package. It’s most likely near the bottom of the front of the packaging. This date code will reveal the precise date the batch was manufactured, as well as the age of the DEF bottle. A laser code is inscribed on the bottle of one gallon containers. A little date code is frequently placed on the product label of larger 2-5 gallon tanks. A larger label will be put on the side or top of larger DEF fluid drums (55 gallons or more) and totes (275-355 gallons). Reading a manufacturer’s code is difficult, as each one is slightly different. The batch number is usually represented by the first digit of the date code, and the next six digits reflect the date the batch was filled at the factory.
How do you identify a DEF Filling Pump Vs. a Diesel Fuel Pump?
A number of safeguards have been put in place to prevent diesel engine fuel from being injected into the DEF tank and vice versa. “The color “green” is the standard for diesel filling stations and pumps around the world. “Blue has been established as the color of choice to signify DEF fluid. DEF is dispensed by a normal 19 mm nozzle, while diesel fuel is dispensed through a 22 mm nozzle. As a last line of defense, the tank cap on almost all trucks should be a “brightly colored blue” to prevent diesel from entering the DEF tank.
What should I do if I accidentally dispense diesel fuel into the DEF?
First and foremost, do not be alarmed. Second, do not start the engine under any circumstances. If you don’t start the engine, putting diesel fuel in the DEF and vice versa (DEF in the fuel tank) will not hurt it. The SCR should detect the presence of a solution other than DEF in the tank and alert the driver through the dashboard ECM readout. It’s also crucial to avoid moving the vehicle. The distribution of fuel into the lines and into the SCR might be caused by moving the vehicle. Draining the tank while the vehicle is still in its original location is the best option. If the engine is started for even a short time, diesel fuel will destroy the SCR catalyst, which is highly expensive to replace and is no longer covered by the manufacturer’s guarantee. If DEF gets into the fuel system and spreads throughout the engine, it will eventually destroy the diesel engine. The DEF is incompatible with the gasoline system lines, which corrode with time.
Will a small amount of DEF in diesel tank?
Owners and operators of trucks must not allow even a trace of DEF to enter their diesel tanks. The diesel fuel system will be contaminated as a result of this. DEF is a urea and water solution. The densities of diesel fuel and water-based DEF are not compatible.
Does DEF shorten engine life?
Owners of three-quarter and one-ton pickup trucks have benefited from the lack of smog equipment on their vehicles for many years. However, in 2008, the EPA mandated that all three-quarter-ton and larger vehicles have diesel particle filters, as well as biannual smog testing that included a comprehensive visual inspection to ensure that all parts were still present. Regulations were tightened in 2010.
Many individuals believed that smog equipment on heavy-duty pickups meant the end of huge power and torque, and many swore they’d never buy another vehicle. Many of those same people, on the other hand, have learned that you should never say never. On the route to achieving smog laws, a funny thing happened: every single manufacturer worked out how to reduce harmful nitrogen oxide levels while producing greater power and torque than ever before.
The use of selective catalytic reduction was a major component of this workaround. To break down the generated NOx into harmless nitrogen and water, most of these systems use diesel exhaust fluid (a mixture of urea and deionized water) injected into the exhaust stream. However, because the fluid is put into the exhaust (a process known as after-treatment technology), manufacturers are able to create as much power as they desire. DEF is normally stored in a separate, insulated, heated tank with a blue filler lid.
1. What are the ingredients in DEF?
DEF is made up of two-thirds deionized water and one-third urea. The American Petroleum Institute keeps a close eye on it. Urea is formed from one of the byproducts of urine in a technical sense. However, because it’s created synthetically, no cats are ever injured in the process.
2. Is it necessary to fill the DEF tank after every fill-up?
No, depending on how much you’re towing, you’ll use roughly 2.5 gallons of DEF every 800 miles or so. You may have a fuel-gauge-like readout (Ram), a digital indicator (GM), or a simple “low” light depending on the year and model of your truck (Ford).
3. DEF fluid is impossible to come by.
Truck stations, as you might assume, stock a variety of DEF brands, sometimes in multigallon containers or at the pump. We’ve discovered DEF at Walmart, TravelCenters of America, Flying J Truck Stops, Love’s Travel Stops, Petro Stopping Centers, and Pilot Travel Centers, to name a few. Furthermore, many car parts stores, such as O’Reilly’s and Advance Auto, sell it by the gallon.
4. A DEF-equipped truck has more disadvantages than advantages.
The only disadvantages we can think of are that the vehicles are a little more expensive, DEF takes up some space in your truck, and it adds a small amount of weight. More efficient combustion, higher fuel efficiency, increased power, lower maintenance, fewer regenerations, less engine wear, plus it emits harmless nitrogen and water into the atmosphere, and it’s very reliable are just a few of the benefits.
5. NOx isn’t a significant concern to begin with.
NOx is a component of exhaust that has been linked to acid rain, smog, and increased global greenhouse gas levels. DEF converts NOx into harmless nitrogen gas and water as part of an SCR system (which is present in the air we breathe). Whether or not you believe these man-made compounds play a part in climate change, NOx is something we don’t need to release into the atmosphere.
6. DEF will evaporate on a hot day.
The DEF would take two years to convert to ammonia and evaporate at a constant temperature of 120 degrees. You no longer need to be concerned about DEF evaporation.
7. DEF will reduce my fuel efficiency.
Quite the opposite is true. Because the manufacturer may tune the engine anyway it wants and then leave the pollutants to the SCR and DEF, most manufacturers have discovered improved fuel mileage (compared to other smog-reduction systems). It is claimed by truck manufacturers that it improves fuel efficiency by up to 5%.
8. This is a brand-new, never-before-used technology.
Incorrect. SCR and DEF have been utilized in commercial and agricultural applications for decades. It’s worth noting that automotive-grade urea is far purer than fertilizer urea. If you utilize a low-quality urea fertilizer, the SCR system will degrade, perhaps causing your truck to break down. It’s possible that it’ll lead the sensors to believe the truck’s DEF tank is empty.
9. DEF is a harsh and dangerous substance.
Hardly. Urea is the active element in DEF, and it’s also found in fertilizers, plastics, animal feed, pharmaceuticals, and various cleaning products (which may explain why some people believe it’s poisonous). Many other fluids in a truck, such as diesel fuel, engine oil, braking fluid, antifreeze, and windshield washing fluid, are less harmful than DEF.
10. What happens if I run out of DEF in my truck?
The EPA mandates that all truck manufacturers include a staged warning system (some with actual gauges) that informs the driver of how near the system is to being empty. Whether a vehicle enters a “limp home” mode, has limited engine power, or restricts the number of times you can start it depends on the car or truck, but it will eventually stop working. Simply said, you should handle your DEF tank as you would your fuel tank; you don’t want to end yourself stranded because you ignored the warnings.
Can I put water in my DEF tank?
Registered. There will be no urea sprayed into the exhaust to convert to ammonia if you put water in an EMPTY DEF tank. Ammonia is required to remove NOX (nitrogen oxides) using the SCR system (Selective Catalytic Reducer).
How do you know when to add DEF fluid?
When it’s time to change your DEF, all newer diesel vehicles include a dashboard warning system. To figure out how much you’ll need, you’ll need to know your engine’s efficiency.
When compared to the amount of fuel used, DEF is consumed at a rate of roughly 2-3%. For a car with a 65-gallon gas tank, this means between 1.2 and 2.0 gallons of DEF will be necessary. DEF should be replenished every third or fourth time you fill up a five-gallon DEF tank. The simplest method to avoid an issue is to simply top off on a regular basis.
What neutralizes DEF fluid?
That’s why, starting in 2010, all diesel trucks were required to have systems dedicated to putting DEF to use. Diesel Exhaust Fluid, which is made up of 32.5 percent urea and 67.5 percent de-ionized water, is sprayed into a vehicle’s exhaust system to aid in the breakdown of NOx emissions, converting them to harmless nitrogen and water. If you’re thinking to yourself, “Urea is a type of urea. You’re on the right brainwave if that sounds oddly like ‘urine.’ When a body metabolizes protein, it produces urea, an organic molecule. (We do, in fact, excrete it as pee.) However, despite DEF’s moniker, “Diesel Exhaust Fluid is really constructed of commercial-grade ureasynthetic ammonia and carbonand is referred to as “pig urine.”
To put it another way, the urea and water in DEF heat up and produce ammonia. The NOx emissions are subsequently neutralized as the ammonia breaks down. The tail pipe emits fewer harmful substances, allowing everyone to breathe a little better.
How do you clean a DEF tank?
Before using, sanitize any containers, funnels, or other equipment that will come into touch with or store DEF. Rinse with distilled water after a thorough cleaning. If distilled water isn’t available, use tap water first, then DEF.
Where does DEF fluid go?
DEF is kept on board the vehicle in a tank and then injected into the exhaust system. On a truck, the storage tank is normally located adjacent to the diesel fuel tank, or near the spare tire location on a vehicle.