DIESEL EXHAUST FLUID: WHAT IS IT AND WHY YOU SHOULD LET THE PROFESSIONALS HANDLE IT

December 16, 2019

Lori Drouillard

One of the main challenges for drivers who have cars with diesel engines is in knowing that some of maintenance that is performed on it cannot always be DIY. For example, handling the Diesel Exhaust Fluid (DEF or AUS 32) required in diesel engines is better off left to professionals. Professionals can make sure that the DEF being used is of the highest quality. When drivers purchase DEF by themselves or leave it to fill-up locations that don’t identify the manufacturer and brand name on the receipt it can lead to engine damage. And while it may technically be true that some drivers can refill this fluid themselves, this approach is not at all recommended. Let’s take a look at just what DEF is, what it does and why you are better off letting experienced professionals refill it in your car.

What it DEF?

Diesel Exhaust Fluid is a caustic solution, which is 32.5% urea and 67.5% de-ionized water. It is injected into the diesel exhaust stream and the heat from the exhaust, the fluid, and a catalyst convert the Nitric Oxide (NOx) into harmless gases. This is done so that cars and trucks that have diesel engines can meet the U.S. Environmental Protection Agency (EPA) emissions requirements.

Reasons You Should Let Professionals Replace the DEF in your Vehicle

  • Professionals are better able to guarantee that the DEF placed in your car is labeled to comply with ISO (International Organization for Standardization) 22241 specifications. The use of low-quality DEF is detrimental to the life of the selective catalytic reductant system and can also affect your car’s ability to reduce harmful NOx emissions. Moreover, low-quality DEF can lead to catalyst poisoning, deposits, and injector/filter clogging.
  • The fluid is difficult to fill for a layperson. DEF is a hazardous chemical and will crystallize on contact with air. Therefore, it needs the skill of certified mechanics in order to ensure that it is filled properly in your car.
  • Monitoring your car’s DEF levels is done electronically, so you will need to keep an eye on your dashboard for a warning regarding this fluid. Professionals are better able to ensure the fluid is full when filling, as there is no dipstick, keeping you in compliance with emissions regulations. Doing this will also protect your engine from costly repairs in the future.

Some things are better left to the professionals. As experts in import car repair, we use API-licensed Diesel Exhaust Fluid to ensure that the DEF we place in your engine meets the high standards required by engine and vehicle manufacturers. Our  import car service center in Michigan  specializes in all areas of  Mercedes repair in Michigan  as well as Volkswagen, Audi, and other European makes.

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