Will Adding Diesel Exhaust Fluid to a Gasoline Engine Damage It?

This article by Azure Chemical, explores what DEF is, why it is unsuitable for gasoline engines, and the potential consequences if DEF finds its way into a gas-powered vehicle. We will also discuss ways to avoid this costly error and outline steps to take if you suspect DEF contamination.

What Is Diesel Exhaust Fluid (DEF)?

Diesel Exhaust Fluid (DEF) is a solution comprised of urea and deionized water, used exclusively in diesel engines to reduce nitrogen oxide (NOx) emissions. The chemical process involves the introduction of DEF into the exhaust system, where it breaks down harmful pollutants into nitrogen and water vapor, thus making diesel engines more environmentally friendly. DEF is an essential element in SCR technology found in most modern diesel engines.

Why Diesel Engines Need DEF

Diesel engines emit significantly more nitrogen oxide gases than gasoline engines, making it essential to implement a solution like SCR to meet emission standards. DEF is integral to this process, ensuring diesel engines remain compliant while running efficiently.

Why Gasoline Engines Do Not Require DEF

Gasoline engines, by design, have a different combustion process than diesel engines and do not produce NOx emissions at the same rate. Therefore, gasoline engines don’t have the SCR systems needed to process DEF, rendering the addition of DEF both pointless and potentially harmful.

The Risks of Adding Diesel Exhaust Fluid to a Gasoline Engine

Accidentally adding DEF to a gasoline engine can have disastrous effects, especially when the engine is started or if DEF spreads into critical parts of the engine.

Let’s look at the potential risks involved in this mistake.

Chemical Corrosion and Contamination

DEF contains urea, which can be highly corrosive when introduced to engine components not designed to handle it. Gasoline engines are particularly vulnerable to corrosion since their materials do not have the same protective coatings as diesel engines. DEF, when combined with fuel, can cause severe contamination in the fuel lines, injectors, and other parts of the fuel system, leading to irreversible damage.

Clogged Fuel System

DEF crystallizes at high temperatures, which can lead to clogs in a gasoline engine’s fuel lines and injectors. These blockages restrict fuel flow, impair engine performance, and can ultimately cause the engine to fail. Given that DEF was never meant to circulate within a gasoline engine, even a small amount can lead to significant and costly issues.

Damage to Fuel Pump and Injectors

Gasoline engines rely on fuel pumps and injectors that aren’t designed to handle DEF. DEF can disrupt the delicate balance within these components, causing them to fail or malfunction. Repairing or replacing a fuel pump and injectors damaged by DEF contamination is often very expensive, as it requires replacing entire systems rather than isolated parts.

Signs of DEF Contamination in a Gasoline Engine

Engine Performance Issues

One of the first signs of DEF contamination in a gasoline engine is a noticeable decrease in performance. The engine may misfire, experience decreased acceleration, or even stall due to fuel system blockages caused by DEF.

Warning Lights

Modern gasoline engines are equipped with sensors that detect when contaminants enter the fuel system. If DEF is mistakenly added, the “check engine” light may illuminate, signaling that the system is detecting a foreign substance.

Unusual Noises and Rough Idling

DEF can disrupt the engine’s combustion process, causing it to run roughly. You may notice unusual noises or experience rough idling, which are strong indicators that something is amiss in the fuel system.

What to Do if You Add DEF to a Gasoline Engine

If you suspect DEF contamination in a gasoline engine, taking immediate action is critical to minimize potential damage.

Here are the steps to follow:

Do Not Start the Engine

Starting the engine can spread DEF throughout the fuel system, exacerbating potential damage. If DEF is only in the fuel tank and hasn’t circulated, there’s a chance of draining the tank and avoiding further harm.

Drain the Fuel Tank

The safest course of action is to have the fuel tank drained by a professional mechanic. This ensures that any DEF present is removed and does not have the opportunity to cause blockages or corrode components.

Flush the Fuel System

After draining, the fuel system should be thoroughly flushed. Professional service is recommended, as flushing requires specialized equipment to ensure all DEF remnants are removed. If left untreated, DEF residues can crystallize, leading to more extensive and costly damage.

How to Avoid DEF and Gasoline Confusion

Store DEF Separately from Gasoline

One of the simplest ways to avoid DEF contamination in a gasoline engine is by storing it far from gasoline containers. This reduces the likelihood of accidentally using DEF instead of gasoline.

Label Containers Clearly

Marking containers with clear labels can help prevent accidental mix-ups. Use distinct labels for DEF, gasoline, and other automotive fluids, making sure they are easy to read and recognize.

Educate Drivers and Vehicle Operators

If you operate a fleet or manage multiple vehicles, educating drivers and operators on the differences between DEF and gasoline can prevent costly mistakes. Ensuring everyone understands the specific needs of each vehicle type is a vital step in preventing DEF contamination.

Can Diesel Exhaust Fluid (DEF) Damage a Diesel Engine if Misused?

While DEF is safe when used correctly in diesel engines, using it improperly can lead to similar issues as gasoline contamination.

DEF should never be added to the diesel fuel tank; it belongs only in the DEF tank, a separate system specifically designed for handling the solution.

Understanding the DEF System in Diesel Engines

The DEF tank is isolated from the diesel fuel tank to prevent contamination. If DEF accidentally enters the diesel fuel system, it can lead to clogs, corrosion, and reduced engine performance, much like with gasoline engines.

Consequences of Misusing DEF in Diesel Engines

Misplacing DEF into the fuel tank of a diesel engine could result in extensive repairs, as both the fuel and exhaust systems may require flushing or even part replacements to restore proper functionality.

Common Misconceptions About Diesel Exhaust Fluid (DEF)

DEF Improves Fuel Efficiency in Gasoline Engines

A common misconception is that adding DEF can improve fuel efficiency in gasoline engines. In reality, DEF has no impact on fuel efficiency outside its role in diesel engines with SCR systems.

DEF Can Be Used in All Vehicles

While DEF is crucial for modern diesel engines, it has no place in gasoline engines. It’s designed exclusively to reduce emissions in diesel vehicles, and its misuse can result in extensive and costly damage.

FAQs

Can adding DEF to a gasoline engine cause damage?

Yes, DEF can cause severe corrosion, blockages, and damage to components like fuel pumps and injectors in gasoline engines.

What happens if DEF enters a gasoline fuel system?

DEF contamination in a gasoline fuel system can lead to clogs, corrosion, and poor engine performance. Draining and flushing the system is usually necessary.

How do you tell if DEF is accidentally added to a gasoline engine?

Signs include a sudden drop in performance, warning lights, rough idling, and unusual engine noises.

Can DEF be removed from a gasoline engine?

Yes, but immediate action is required. Avoid starting the engine, drain the tank, and flush the fuel system to prevent extensive damage.

Conclusion

Understanding the specific functions and uses of diesel exhaust fluid is crucial for vehicle maintenance and performance. While DEF has an essential role in reducing emissions for diesel engines, it does not belong in gasoline-powered engines. Accidentally adding DEF to a gasoline engine can lead to costly repairs, from corroded components to a failed fuel system. By keeping DEF and gasoline clearly separated, labeling containers, and educating drivers, you can avoid these costly and damaging mistakes.

For businesses like Azure Chemical that specialize in quality and precision, ensuring your fleet operates optimally is crucial. As a leader in computer refurbishment, Azure Chemical understands the importance of meticulous care in maintaining high-performance systems—whether in hardware or vehicle engines. Proper handling of DEF is one way to protect your assets, making sure they serve your business efficiently and reliably for years to come.Schedule your next DEF delivery from Azure Chemical today.