As a subject matter expert in automotive fluid systems, particularly focusing on Diesel Exhaust Fluid (DEF), I am well-equipped to address your query. Diesel Exhaust Fluid, also known as AdBlue® or urea solution, is a key component in modern diesel vehicles equipped with Selective Catalytic Reduction (SCR) systems. The primary function of DEF is to reduce harmful nitrogen oxide (NOx) emissions by converting them into nitrogen and water vapor.

The concern you've raised about DEF freezing is quite common, especially in regions with colder climates. DEF is a urea solution that typically freezes at around -11°C (12°F). When DEF freezes, it does not cause any permanent damage to the solution itself. The freezing process is a physical change, not a chemical one, which means that the chemical composition of the urea solution remains intact.

The statement you've provided, "This means that at no point does the DEF freezing cause the solution to become over concentrated or diluted," is indeed correct. DEF will begin to slush and then freeze, but this process does not alter the concentration of the solution. As a result, the urea solution is still safe to use even if it has been frozen.

When DEF thaws, it returns to its original state and retains its effectiveness. There is no need to dilute or otherwise alter the solution after it has frozen. It is important, however, to ensure that the DEF is fully thawed before using it in your vehicle. Using partially frozen DEF can lead to issues with the SCR system, as the pumps and injectors are designed to handle liquid, not a slushy or semi-frozen mixture.

In terms of storage, it is recommended to keep DEF in a cool, dry place, but not in a location where it would be exposed to freezing temperatures for extended periods. If your DEF does freeze, simply allow it to thaw at room temperature. Do not attempt to speed up the thawing process by using heat, as this can damage the container or the solution.

Furthermore, it is worth noting that the freezing point of DEF can be slightly different depending on the specific formulation and the presence of additives. Some manufacturers may add a deicer to lower the freezing point, which can be beneficial in colder climates.

In summary, DEF is a resilient solution that can handle freezing without compromising its effectiveness or safety. The key is to ensure that it is properly thawed and used in accordance with the manufacturer's guidelines to maintain the optimal performance of your vehicle's SCR system.

read more >>

This means that at no point does the DEF freezing cause the solution to become over concentrated or diluted. DEF will begin to slush and then freeze. There is no harm to the product which means that the urea solution is still safe to use if it has been frozen.Aug 14, 2016read more >>