3 Easy Testing Methods

Quality is of the utmost importance when handling and delivering Diesel Exhaust Fluid (DEF). We'll take you through three proper ways you can test DEF quality.

Visual Test

You can examine your DEF by visually checking for clarity, ensuring there are no contaminants or debris floating in the fluid. This will only check for color and debris in the product that could potentially clog filters on the SCR system.

If the DEF is any color but clear, you may have a problem with mineral contamination. This method will not provide the concentration of urea to water or any mineral contaminates.

Handheld Test

You can use a handheld DEF Chek Tester or purchase an electronic handheld refractometer like the Misco DEF-201 at a cost of around $360. This will measure the concentration specifications of the fluid to ensure 32.5% of the fluid is urea.

If using the DEF Chek Tester, you will fill the tester to the designated line then read number of floating discs which displays the urea concentration of the fluid. If none, 1 or 3 discs are floating then you should replace your fluid.

  • 0 Discs < 29% Urea Concentration
  • 1 Disc 30% Urea Concentration
  • 2 Discs 32.5% Urea Concentration
  • 3 Discs 35% Urea Concentration

Certified DEF Testing Lab

You can send samples of your DEF to an outside lab. Most lab tests will measure everything to the ISO 22241 specification, debris, concentration and the presence of any contaminates. This costs roughly $800 per sample.

MYTH – The America Petroleum Institute (API) enforces a strict testing process to ensure each supplier’s Diesel Exhaust Fluid meets the ISO standard 100% of the time.

FACT – API requires DEF suppliers to submit documentation of their source points and submit an initial lab sample report. API performs random testing of DEF in the marketplace to check product specifications.