When pumped into the exhaust, DEF transforms NOx emissions into safe nitrogen gas and water vapor. As a result, diesel engines emit less smog and other air pollutants.
Most diesel vehicles manufactured after 2010 for the North American market are required to have DEF systems. This includes light-duty trucks, heavy-duty trucks, buses, and other large diesel vehicles. DEF tanks need to be periodically refilled, usually at oil change intervals. Maintaining the DEF system and filling the tank is crucial for emissions compliance. Keep reading this blog post by Azure to find out about diesel exhaust fluid’s overall quality and how long does it last.
Contents
Does DEF Have an Expiration Date?
Diesel Exhaust Fluid (DEF) does have a limited shelf life and can go bad over time if not stored properly.
Though DEF itself is a stable chemical solution, the urea concentrate within it can start to decompose and degrade in quality after 12-18 months.
Most DEF manufacturers recommend using opened bottles of DEF within 12 months for optimum performance. After around 18 months, the urea concentrate within DEF starts to break down into ammonia and carbon dioxide, reducing the effectiveness of the DEF.
The shelf life of DEF depends on how it is stored. DEF can degrade faster if stored in less-than-ideal conditions like high heat or sunlight exposure. But if kept in a cool, dark place around room temperature, DEF can often last up to 18 months before going bad.
The degradation causes DEF to be less effective at reducing NOx emissions. Using degraded DEF can lead to clogged filters, engine issues, and failure to pass emission tests. So, it’s important to watch expiration dates and signs of deterioration before pouring from a bottle and sitting around for a while. Replacing aged DEF ensures optimal exhaust treatment.
Signs of Bad or Degraded DEF
Diesel exhaust fluid (DEF) is formulated to remain effective for long periods when stored properly. However, there are a few signs that indicate DEF may have degraded and is no longer good to use in your vehicle:
Change in Color
Fresh DEF is clear and colorless. If your DEF has turned yellowish, cloudy, or dark, it has likely been contaminated or begun to degrade. The color change is one of the first visual clues.
Crystallization
DEF contains urea and water, which can crystallize into a solid if the solution becomes too concentrated. Crystals or slushy texture means the DEF is no longer effective and should not be used.
Contamination
DEF can become contaminated by dirt, debris, other chemicals, or foreign substances. If you notice floating particles, sediment, or an oily sheen, the DEF has been compromised and should be replaced. Even a small amount of contamination can degrade the DEF over time.
Checking DEF periodically for signs of deterioration can help prevent major headaches. If you notice any change in color, crystallization, or contamination, the DEF should be completely flushed and replaced for optimal performance. Never try adding water or other additives to “revive” degraded DEF.
Consequences of Using Degraded DEF
Using degraded or contaminated diesel exhaust fluid can lead to some serious issues with your vehicle’s emissions system.
Here are some of the potential consequences:
Fault Codes and Check Engine Lights
One of the first signs of contaminated DEF is that you may get a fault code triggered and the check engine light coming on. This indicates an issue detected with the selective catalytic reduction system. The DEF quality sensor detects the degradation and throws a code.
Clogged Filters and Lines
As DEF ages, it can begin to crystallize, especially if it gets too cold. These crystals can build up and clog filters and lines that are part of the DEF system. This restricts the flow of fluid and can damage the system. Replacing clogged filters and cleaning lines can be an expensive repair.
Increased Emissions and Test Failures
The DEF helps reduce nitrogen oxide emissions from diesel vehicles’ exhaust. If you use degraded DEF, it won’t effectively help with this reduction. That means your vehicle may emit higher levels of these harmful gases. It could also lead to the failure of state emissions testing, which requires diesel vehicles to pass strict NOx limits. Using fresh DEF is required to control emissions.
So, in summary, contaminated diesel exhaust fluid can lead to costly repairs, headaches from engine codes, and even emissions test failures in severe cases. That’s why it’s so important to store and maintain DEF properly and replace it when it’s degraded. Fresh DEF helps ensure your diesel pickup or truck runs cleanly for many miles.
Proper DEF Storage
Diesel exhaust fluid (DEF) should be stored properly to maintain quality and maximize shelf life. Here are some guidelines for proper DEF storage:
- A cold, dry spot away from the sun is where DEF should be kept. Over time, heat and sunlight can deteriorate DEF.
- The ideal storage temperature is below 90°F. If DEF gets too hot, it can start to evaporate or decompose. Temperatures above 90°F will accelerate deterioration.
- Keep DEF containers tightly sealed and clean. Any contaminants or dirt that get into the DEF can reduce its purity and cause deposits in the DEF system.
- Avoid storing DEF directly on concrete floors. The urea in DEF can crystallize from the moisture if stored on cool concrete.
- DEF has the potential to freeze in very cold temperatures below 12°F. Frozen DEF will thaw out without any degradation once temperatures rise. Avoid repeated freeze-thaw cycles, though.
- Check DEF containers and storage areas periodically for signs of crystallization, contamination, or leaks. Address any issues promptly.
- Use clean funnels and containers when handling or transferring DEF to avoid introducing impurities.
Proper DEF storage in a cool, dry place with sealed containers will help maintain the fluid’s quality and longevity. Following the above guidelines can prevent DEF deterioration and extend its shelf life.idelines can prevent DEF deterioration and extend its shelf life.
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Extending DEF Shelf Life
Even when properly stored, DEF has a shelf life of approximately 18 months before it starts to degrade.
However, some steps can be taken to extend the lifespan of stored DEF:
Add Stabilizers to Bulk Storage Tanks
Adding stabilizing chemicals like fuel biocides to large DEF storage tanks can help extend the fluid’s shelf life by preventing microbial growth. These additives work to inhibit bacteria, fungi, and algae. Always follow additive manufacturer recommendations for dosage and tank maintenance when using stabilizers.
Use Oldest DEF First With a Regular Inventory Turnover
Using a first-in, first-out (FIFO) approach to your DEF supply will ensure that older fluid gets used before degradation occurs. Monitor expiration dates and regularly cycle in fresh DEF to replace older stock. Proper inventory management is key.
Monitor Tanks for Signs of Degradation
Check DEF tanks and totes regularly for any signs of contamination or decreased performance. Look for unusual odors, color changes, or sediments, which could indicate DEF degradation. Laboratory analysis can identify reduced ammonia content. Promptly filter or replace DEF if deterioration is suspected.
Proper DEF Disposal
Diesel exhaust fluid that has degraded and can no longer be used in engines must be disposed of properly. Do not pour DEF down the drain or discard it in your regular trash. The urea in DEF can harm the environment if disposed of carelessly.
Instead, bring unusable DEF to an approved waste management center that handles automotive chemicals. Call ahead to confirm they can properly dispose of the DEF. Some DEF retailers also accept old or bad DEF for proper disposal. Check with a local auto parts store, truck stop, or DEF supplier to see if they offer this service.
Disposing degraded diesel exhaust fluid correctly is important to avoid pollution and damage to sewers or septic systems. With proper storage and handling, DEF has a long shelf life. But no matter how careful you are, occasionally, DEF can go bad. Make sure to discard it safely when that happens. Handling DEF waste properly protects the environment and water sources.
Replacing Degraded DEF
If your diesel exhaust fluid has gone bad or degraded in quality, it’s important to completely replace it to avoid damaging your vehicle’s emissions control system.
Here are the steps for properly replacing degraded DEF:
Drain the Entire DEF System
Drain the entire DEF system, including the tank. If the drain valve at the tank bottom is opened, all of the liquids will drain. It is advised to have a container ready to hold the DEF that has been drained.
Flush the Lines
Once fully drained, flush the lines to remove any remaining contaminants. Distilled water works best for this. Run distilled water through the lines until the drained liquid runs clear.
Refill the Tank and Lines
Refill the tank and lines with new, high-quality DEF that meets ISO 22241 specifications. Reputable diesel engine manufacturers recommend using DEF from a sealed container within six months of opening to ensure optimal quality. Only use DEF certified by the API.
Reset Any Dash Lights or DEF System Warnings
Reset any dash lights or DEF system warnings once the new fluid is added. Most vehicles will automatically detect the new fluid and reset the warnings.
Completely flushing out old, degraded DEF and replacing it with fresh product will help restore your emission control system to proper working order. Avoid further DEF deterioration by storing it properly and checking expiration dates.
Preventing DEF Deterioration
When stored for an extended period or in unsuitable conditions, diesel exhaust fluid (DEF) can degrade.
To prevent DEF from going bad or losing effectiveness, follow these guidelines:
Buy DEF Only From Reputable Dealers
Buy DEF only from reputable dealers and ensure it comes in a sealed container. Reputable DEF manufacturers follow stringent production standards to minimize contamination and ensure a long shelf life. Check that the DEF container has all the necessary labeling showing the production/expiration date, manufacturer, and correct urea concentration.
Use DEF Within 12 Months of the Production Date
Use DEF within 12 months of the production date, if possible. While DEF can last up to 18 months before degrading when stored properly, aim to use it within 12 months of manufacture for maximum effectiveness.
Store DEF in a Cool, Dry Place
Store DEF in a cool, dry place indoors between 12°F to 86°F. Avoid storing DEF in areas that experience extreme temperatures or direct sunlight. DEF freezes around 12°F, so protect it from freezing.
Keep the DEF Container Sealed
Keep the DEF container sealed when not in use. Only open the DEF container at the time of use to avoid contamination. Do not transfer DEF between containers, as it risks contamination.
Check DEF Visual Quality Before Use
Check DEF visual quality before use. Clear DEF with a slight ammonia smell is good quality. Discolored, cloudy, or smelly DEF should not be used.
Following these best practices when buying, storing, and handling DEF will minimize deterioration and help extend DEF’s shelf life. Using fresh DEF within 12 months ensures optimal emissions control performance.
Frequently Asked Questions
Does DEF Have an Expiration Date?
Yes, DEF can degrade over time. Its shelf life is typically stated as two years from the date of manufacture if stored in optimal conditions. However, exposure to direct sunlight or high temperatures can significantly reduce this shelf life.
How Should DEF be Stored to Maximize its Shelf Life?
DEF should be stored in a cool, dry, well-ventilated area and out of direct sunlight. The optimal storage temperature is between -11°C (12°F) and 30°C (86°F). Storing DEF properly can help maintain its quality and extend its shelf life.
How Can I Tell if DEF Has Gone Bad?
Signs that DEF may have degraded include discoloration, the presence of particles or sediment, or a noticeable change in odor. If DEF appears cloudy or has solid particles, it should not be used.
Conclusion
Diesel exhaust fluid (DEF) plays an important role in reducing harmful emissions from diesel engines. Lowering the toxic emissions produced by diesel engines. DEF does not expire, but contamination or poor storage can cause it to lose quality over time. Signs of degraded DEF include cloudiness, unusual coloring, crystallization, and foreign particles or residue. Decreased DEF can lead to serious issues like blocked DEF lines, not passing emissions tests, and even engine damage if left unaddressed.
Maintaining the efficacy and integrity of DEF requires proper storage. To extend the shelf life of DEF, store it in sealed containers between 12°F (-11°C) and 86°F (30°C). DEF also lasts longer when stored in opaque containers out of direct sunlight. However, despite good storage practices, DEF will gradually degrade after around a year.
The bottom line is that DEF needs to be kept fresh to work properly. Check your DEF periodically and replace any batches that show signs of deterioration. Protecting your diesel vehicle’s emissions system and engine is a small investment. Take your time with degraded DEF, leading to costly repairs. Maintaining high-quality DEF is essential for compliance with emissions standards and optimal truck performance. Get in touch with Azure Chemical to schedule your high-quality DEF today!
