Diesel Blend for Winter: When to Use Additives and When to Use Kerosene

Maintaining fuel performance in cold weather is essential for keeping diesel engines running smoothly. Choosing the correct diesel blend and understanding when to use winter additives versus kerosene can save money and prevent costly operational issues.

Why Does Diesel Need Winter Treatment?

As temperatures drop, the paraffin wax in diesel begins to crystallize, forming sheets that can clog fuel filters and prevent the engine from running. Cold-flow Improvers works by altering the structure of these wax crystals, turning them into needle-like shapes that can pass through filters more easily.

There are 3 important temperatures to consider with diesel fuel:

• Cloud Point: The temperature where wax begins to crystallize, causing the fuel to appear hazy. The fuel will still work at the cloud point.
• Cold Filter Plugging Point (CFPP): The temperature where diesel fuel stops flowing freely through a standard fuel filter. This is the point where “gelling” occurs.
• Pour Point: The lowest temperature at which diesel fuel remains fluid enough to pour. It’s rare for diesel fuel to reach a level where it cannot physically be poured.

Cost Savings with Additives

Many fleets utilize high kerosene (also known as #1 diesel) blends to ensure their diesel works all winter long. Kerosene blends could range anywhere from 90/10 blends (10% kerosene) to 50/50 blends (50% kerosene) – some fleets even go beyond 50% blends. This approach is certainly a safe way to ensure winter performance (and may be a necessary evil, as discussed below), but it adds significant costs that may not always be necessary.

Over the last three years, ULSD #1 has cost an average of 52 cents more than regular diesel fuel – at times even exceeding a dollar premium. Multiply the premium by the percentage blend, and you’ll see your added cost – for instance, a 70/30 blend would cost 15.6 cents more than regular diesel.

Winter additives, also known as Cold-flow improvers, are designed to modify wax crystals in diesel fuel, preventing them from clumping together and clogging filters. These additives lower the Cold Filter Plugging Point (CFPP), allowing fuel to flow at lower temperatures.

Cold-flow improvers are significantly cheaper than blending large amounts of kerosene into diesel fuel. Additives can lower the operable temperature of diesel fuel by 15-20°F, reducing the need for kerosene and helping fleet owners manage costs more effectively.

Additionally, additives have water-dispersing properties, helping to minimize the risk of ice formation in fuel tanks. They can also contain cetane boosters, which improve ignition quality and overall engine performance. You can learn more about the types of winter additives here.

Fleet owners and operators can use temperature charts and zone-specific blending guides to determine the optimal ratio for their region. Zones with extreme cold may require a blend of kerosene, while milder zones can rely more heavily on winter additives.

When Kerosene Becomes Necessary

However, when temperatures drop to extremes—such as -20°F, common in places like Minnesota—kerosene becomes essential. While winter additives can reduce the need for kerosene, it has its limits. At such extreme temperatures, a 70/30 diesel-to-kerosene blend, combined with additive, is often required for reliable performance.

Many fleets still use a 50/50 blend all winter long based on old conventional wisdom, which is not a cost-effective approach. This blend costs much more per gallon than regular diesel and results in lower fuel efficiency. Instead, it’s more economical to use winter additives regularly with a lighter kerosene blend, for example an 80/20 or 70/30 blend, and reserve the heavier blends for extreme weather events.

Kerosene lowers the CFPP more effectively than additives alone but at a higher cost. It also reduces the energy content of the fuel, impacting mileage and engine efficiency.

Prevention is Key

Preventing fuel gelling is far more efficient than trying to fix it. Ensuring tanks are properly treated with cold flow additives before temperatures plummet saves both time and money. Proper blending, regular fuel testing, and tank maintenance are all critical steps in a successful winter fuel management strategy.

Fuel system maintenance also plays a crucial role. Water and sediment buildup in tanks can worsen winter fuel issues. Regular tank inspections, fuel polishing, and microbial growth testing can help fleet operators identify and address potential problems before they escalate. You can learn if your tanks are ready for winter here.

Plan Ahead and Reduce Costs

Just as planning your fleet’s routes is crucial for efficiency, properly preparing your fuel for winter is essential for avoiding costly breakdowns. Mansfield’s Arsenal ColdPRO is a program to improve your fuel’s cold-weather performance, offering consistent and accurate treatments, minimizing kerosene cost, and performing nationwide fuel testing.

With the right strategy in place, you can keep your fleet running smoothly throughout the winter season, regardless of where you operate. If you haven’t already, contact Mansfield to learn more about Arsenal ColdPro. Don’t wait; contact us today to secure a worry-free winter for your fuel needs.