Minnesota Diesel Helpline

05/29/2026

The Helpline conducts a test called Thermal Stability (ASTM D6468), which exposes fuel to heat to evaluate its resistance to thermal degradation. The fuel sample is filtered and put in a test tube, then heated to 300F for 3 hours. The fuel is cooled and filtered again. The amount of light that can pass through the filter pad is measured, resulting in a “reflectance rating.” A reflectance rating of 70% or higher indicates clean, stable fuel. Lower ratings suggest the fuel has degraded, forming deposits that can clog filters and fuel injectors.

The difference in these samples is dramatic: the fuel on the left measured just 6% reflectance—the worst result the Helpline has ever seen—indicating severely degraded fuel unlikely to perform well in an engine. The sample on the right measured 96%, showing excellent fuel stability.

04/22/2026

03/30/2026

Here is a reminder that Minnesota diesel fuel sill transition from B5 to B20 over the next month.

03/18/2026

It's National Biodiesel Day, celebrated on Rudolf Diesel's birthday. Rudolf Diesel is the inventor of the diesel engine, which he originally designed to run on vegetable oil. Test your knowledge about biodiesel below.

02/26/2026

The Helpline has seen diesel cloud points in the double digits this past winter – higher than normal. Cloud point is the temperature where the first wax crystals form and look like a wispy cloud. Many areas have low temperatures forecast in the single digits or even lower over the next week. So if your fuel has a 10F cloud and the temperature is 6F, and the fuel is not winterized, you might have problems until it warms up. Mother Nature is unpredictable! It is important to continue to manage fuel for winter temperatures. HOT TIP: Winterization of fuel by blending No. 1 diesel or using winter additives must take place 10 degrees above the cloud point.

01/30/2026

The City of Edina talks about utilizing B100 in their snowplows:

This fall, work to make the City’s fleet of heavy vehicles more environmentally friendly shifted into high gear. Large dump trucks used for everything from h...

11/11/2025

Here's a great explanation of Selective Catalytic Reduction SCR.

What is Selective Catalytic Reduction (SCR)? It's an advanced active emissions control technology system that reduces tailpipe emissions of nitrogen oxides (NOx) down to near-zero levels in newer generation diesel-powered vehicles and equipment. The SCR system involves several components packaged together with other parts of the emissions control system. Each manufacturer has its own variations of the type and sequencing of different components in the system.

Learn more: https://bit.ly/47yTOYS

11/06/2025

Winter is coming soon. Now is the time to act if you need your diesel equipment to operate in winter.

10/31/2025

Don’t Let Tank Maintenance Nightmares Haunt You!

09/29/2025

Fall Fuel Reminders