DEF is a mixed solution of 32.5% high-purity urea and 67.5% deionized water. When injected into the exhaust, DEF breaks down NOx into nitrogen and water vapor, which are harmless to breathe. This chemical reaction helps neutralize the pollutants in diesel exhaust.
All diesel vehicles and equipment produced after 2010 use selective catalytic reduction (SCR) systems that require DEF. This fluid is essential for reducing smog-causing emissions and enabling diesel engines to operate cleanly. This blog post by Azure will provide more insight about the main reasons of degraded DEF quality.
Contents
Main Reasons for the Poor Quality
Diesel Exhaust Fluid (DEF) can become poor quality and degraded in a few key ways:
Contamination
DEF has the potential to become contaminated from improper handling, storage, and dispensing. Things like dirt, debris, other fluids, and water can inadvertently get mixed into DEF, reducing its purity. Even small amounts of contamination can compromise DEF quality and performance.
Improper Storage
DEF needs to be stored properly to maintain its quality. If stored at too high or low temperatures for extended periods, DEF can start to degrade. Freezing, thawing, and overheating in storage tanks, dispensers, or vehicles can impact DEF over time.
Mixing Errors
Errors can occur when mixing DEF concentrate and water to dilute it. If the concentration is off and the DEF-water ratio isn’t 32.5/67.5, the diluted DEF fluid will be poor quality. Even small mixing errors can throw off the concentration.
Proper handling and storage according to manufacturer guidelines is important to prevent DEF from becoming contaminated or degraded. Precise mixing procedures should be followed as well. Small storage, dispensing, and mixing mistakes can reduce the purity and quality of diesel exhaust fluid over time, leading to performance issues.
Detection
Knowing the signs of poor-quality DEF is crucial for preventing damage to your vehicle. There are a couple of primary methods for detecting low-quality DEF:
Visual Inspection
Check the DEF tank and supply lines for signs of deposits, crud, or crystallization. Poor quality diesel exhaust fluid is more likely to leave behind residue and buildup. The DEF may also appear cloudy or discolored if it has impurities or is contaminated. Pure DEF should be clear and colorless.
Any abnormal odor is also a red flag. DEF naturally has an ammonia-like smell, but a particularly strong odor can indicate chemical breakdown of the area.
Dipstick Testing
A dipstick or refractometer is a more accurate way to test DEF quality. These tools measure the concentration of urea in the fluid.
DEF specifications require the urea content to be 32.5%. Any reading lower than 30% indicates weak or diluted fluid. A reading higher than 34% means there is too much urea, and the fluid does not meet specifications.
Out-of-spec, urea concentration levels, will set off the malfunction indicator lamp and eventually cause the vehicle to enter a power-reduced mode until the DEF is fixed. Dipstick testing regularly provides an easy way to monitor quality.
Effects on the Engine
Using poor-quality diesel exhaust fluid can lead to serious issues for the engine and emissions control system. One important part of the selective catalytic reduction (SCR) system, which lowers nitrogen oxide (NOx) emissions, is the diesel exhaust fluid (DEF).
If low-quality or contaminated DEF is used, it can cause the following problems:
Increased NOx Emissions
With poor quality diesel exhaust fluid, the SCR system cannot properly convert the NOx gases into harmless nitrogen and water. This leads to elevated NOx emissions exceeding the legal limits.
Damage to SCR Components
Contaminants or impurities in poor-quality DEF can cause deposits in the SCR catalyst and injectors. This impairs the DEF injection and NOx conversion, eventually leading to permanent damage to the SCR system.
Engine Derate
When the DEF quality is detected as poor, the computer will initiate an engine derate. This limits engine power and speed, encouraging the driver to address the DEF issue. If not fixed, it can result in the vehicle eventually not starting.
Costly Repairs
The SCR system is expensive, with the catalyst costing over $1,000 alone. Contaminated or poor-quality DEF that damages these components will require expensive repairs and downtime. Using the recommended DEF as specified by the manufacturer can prevent these issues.
So, in summary, poor quality diesel exhaust fluid leads to increased emissions, damage to expensive SCR components, derated engine performance, and ultimately, costly repairs. Using DEF meeting ISO 22241 standards from reputable sources is crucial to avoid these problems.
OBD Trouble Codes Related to Poor Quality DEF
On-board diagnostics (OBD) uses trouble codes to indicate issues with the DEF system.
Three common codes related to poor quality diesel exhaust fluid include:
P20EE
This code indicates that the NOx reduction system has detected poor quality or degraded DEF. It means the DEF fluid does not have the expected concentration of urea.
P20E8
This code is set when the DEF tank temperature is too high, generally above 122°F (50°C). High tank temperatures can deteriorate DEF quality over time.
P20E9
This code indicates the DEF tank temperature stayed too low, generally below 12°F (-11°C), for an extended period. Freezing and thawing DEF repeatedly reduces its quality and concentration.
These OBD trouble codes point to low-quality DEF as the root cause. Technicians use OBD scanners to read these codes and diagnose issues with DEF. The codes help pinpoint if poor DEF quality is responsible for problems with the selective catalytic reduction system.
Solutions for Poor Quality DEF
If your diesel exhaust fluid has degraded and becomes poor quality, there are a few solutions to restore proper functioning:
Drain, Flush and Replace
The most direct solution is to drain the contaminated DEF tank and flush the system completely. Make sure to capture any spilled fluid and dispose of it properly. DEF contains urea and can damage paint and vegetation.
After draining, refill the tank with new, high-quality DEF that meets ISO 22241 standards. Running a few tankfuls of fresh fluid will help flush any remaining contaminants.
Restore Proper Fluid Concentration
Using a refractometer, test the DEF concentration. Pure DEF is 32.5% urea and 67.5% deionized water. If the urea content has dropped below 31.8% or increased above 33.2%, the DEF may trigger errors.
Add distilled water or pure urea to adjust the concentration to the ideal 32.5% level. Make small adjustments in increments of 5-10% at a time. Then retest until within specification.
Properly diluted DEF will restore proper functioning and turn off any incorrect diagnostic trouble codes or warning lights. In the future, maintain fluid quality by storing DEF in cool, dry areas and avoiding contamination.
Prevention
There are two key ways to prevent poor-quality diesel exhaust fluid:
Proper Storage
Diesel exhaust fluid (DEF) must be stored properly to avoid contamination or degradation. Here are some tips:
- DEF should be kept out of direct sunlight in a cool, dry area. Keep out of storage spaces that get hotter over 86°F.
- Use only DEF-approved containers, tanks, pumps, and hoses. Avoid contact with incompatible materials.
- Keep the storage tank capped and sealed when not in use.
- Avoid water contamination by checking for condensation and moisture in the storage tank.
- Inspect storage tanks and transfer equipment regularly for cleanliness, leaks, etc.
- Follow all manufacturer storage instructions and expiration dates.
Avoid Contamination
It’s critical to prevent anything from entering and contaminating the DEF supply. Here’s how:
- Thoroughly clean any equipment before transfer or use with DEF. Avoid cross-contamination.
- Use dedicated DEF-only funnels, pumps, tanks, and more. Never reuse equipment meant for other fluids.
- Keep the area around storage and fill sites clean and free of other chemicals, dirt, etc.
- When topping off the DEF tank, clean the nozzle and avoid overfill.
- Never pour leftover or used DEF back into the supply tank.
- Keep DEF fill caps sealed and check for tampering. Someone could intentionally contaminate it.
Properly storing DEF and avoiding contamination can prevent poor quality.
Quality Standards
Industry groups have established stringent quality standards for diesel exhaust fluid (DEF). The two primary standards-setting bodies are the International Organization for Standardization (ISO) and the American Petroleum Institute (API).
The API administers a voluntary DEF certification program that sets quality standards and verifies DEF producers. API certification involves testing the DEF for content, stability, and freezing point. Only DEF meeting the API technical specification can display the API certification mark on the packaging.
ISO 22241 is the international standard that specifies DEF’s requirements and test methods. It defines the allowable levels of impurities and decomposition products in DEF. The standard also sets testing procedures to verify DEF concentration, appearance, density, alkalinity, and refractivity.
DEF must comply with API and ISO standards to ensure optimal performance. Reputable DEF suppliers voluntarily submit their products for certification. Using DEF from a certified producer minimizes the risk of contamination and engine damage. Checking for API and ISO certification marks on DEF packaging is an easy way to verify quality.
Cost of Poor Quality
Poor-quality diesel exhaust fluid can lead to significant repair costs, downtime, and fines.
When low-quality DEF causes damage and clogs components of the exhaust system, expensive repairs may be needed. Components like DEF injectors, sensors, the catalytic converter, and even the turbocharger and engine itself may require replacement. Labor costs quickly increase as mechanics take time to diagnose issues and make repairs.
Truck downtime is another major cost. If a truck breaks down and can’t operate due to DEF quality problems, it loses revenue from hauling freight. The trucking company still has to pay drivers during downtime, increasing costs. Rental or replacement trucks may be needed in the interim.
Regulatory fines can also be issued if DEF quality issues cause trucks to exceed emissions limits. Trucking fleets are responsible for compliance and can face steep fines. For example, the California Air Resources Board enforces fines of up to $37,500 per truck for emissions violations.
The costs of poor quality diesel exhaust fluid through repairs, downtime, and fines make it critical to prevent problems using high-quality fluid from reputable suppliers. The savings in the long run are significant.
Frequently Asked Questions
What is Diesel Exhaust Fluid (DEF)?
Diesel Exhaust Fluid is a urea-based solution used in Selective Catalytic Reduction (SCR) systems to reduce nitrogen oxide emissions from diesel engines.
How Can DEF Quality Be Compromised?
DEF quality can be compromised by contamination, incorrect formulation, improper handling, exposure to extreme temperatures, and degradation over time.
What Are Common Contaminants in DEF?
Common contaminants include water, dust, dirt, metals, and chemicals that can accidentally mix with the fluid during production, transportation, or storage.
How Does Incorrect Formulation Affect DEF Quality?
Incorrect formulation, such as incorrect urea concentration, can lead to reduced effectiveness in reducing emissions and can potentially damage the SCR system.
Conclusion
Maintaining high-quality DEF is critical for the proper functioning of your vehicle’s SCR system and emission controls. Poor quality diesel exhaust fluid can lead to many issues, from engine derates and shutdowns to damage to SCR components, increased emissions, voiding of warranties, and failed inspections.
DEF must meet ISO 22241 quality standards. Look for API certification and reputable brands when purchasing DEF. Avoid any signs of contamination, dilution, or degradation. Properly store and handle DEF to preserve quality. Monitor the DEF level and refill it regularly with fresh fluid. Stay alert to any OBD codes or symptoms of DEF problems, and service the SCR system if issues arise. A well-maintained DEF system protects your investment in the vehicle, maintains eco-compliance, and keeps you on the road.
By understanding what poor quality DEF is, how to prevent it, and how to respond if it occurs, you can avoid negative impacts on your vehicle, operations, and bottom line. High standards for DEF quality will ensure optimal performance and reliability. In addition, you can always schedule your high-quality DEF delivery from Azure Chemical anytime. Contact us today!
