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How to Manage the Transition to Winter Grade Diesel Fuel

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Tire Traction & Fuel Efficiency

Winter weather can pose significant challenges for diesel-powered vehicles, particularly commercial trucks. Transition to winter grade diesel fuel ensures your fleet remains operational during the colder months. This comprehensive article will address managing this transition effectively, answering key questions such as how to prepare your diesel for winter, whether additives are necessary, when to switch and do the transition to winter grade diesel fuel, and how to blend diesel fuel for winter.

How to Prepare the Transition to Winter Grade Diesel Fuel

  1. Test Your Battery

Cold weather can significantly reduce battery efficiency. Before winter sets in, test your battery to ensure it can handle the increased load. A battery load tester can provide accurate results, but many auto shops offer free battery testing services. If your battery is weak, consider replacing it to avoid no-start situations during the winter months.

  1. Check Belts, Boots, and Hoses

Cold temperatures can make rubber components brittle and prone to cracking. Inspect your vehicle’s belts, boots, and hoses for any signs of wear and tear. Replace any damaged parts to prevent breakdowns.

  1. Inspect and Change Coolant

Coolant plays a vital role in maintaining engine temperature. Ensure your coolant is suitable for sub-zero temperatures by checking its concentration and condition. A 50/50 mix of water and coolant is typically recommended but always refer to your vehicle’s manual for specific guidelines.

  1. Inflate Tires Properly

Cold weather can cause tire pressure to drop, affecting traction and braking. Regularly check and maintain your tire pressure according to the manufacturer’s recommendations. Consider switching to winter tires if you operate in regions with heavy snowfall.

  1. Warm Up the Engine

Cold starts can be harsh on your engine. Use tools like glow plugs and block heaters to warm up the engine before driving. This practice helps prevent damage and ensures smoother operation.

Do I Need to Add Anything to My Diesel Fuel in the Winter?

Use of High-Quality Additives

If you cannot access winter-grade diesel fuel, additives are a viable alternative. These additives help prevent the formation of wax crystals in the fuel, which can clog filters and fuel lines. Products like Hot Shot’s Diesel Winter Anti-Gel and AR6300 Winter Diesel Treatment are designed to improve fuel flow and prevent falling to extremely low temperatures.

How to Use Additives:

  • Add the specified amount of additive to the fuel tank before refueling to ensure proper mixing.
  • Use additives each time you fill your tank when temperatures drop below 32°F to maximize effectiveness.

Replace Your Fuel Filter

An old or dirty fuel filter is likely to clog in cold weather. Replace your fuel filter before winter and keep a spare in your truck. This precaution helps maintain fuel flow and reduces the risk of breakdowns.

When Should I Do the Transition to Winter Grade Diesel Fuel?

Timing the Transition

Switch to winter-grade diesel fuel when temperatures consistently drop below 35°F. Winter diesel is typically available from mid-November to mid-March, depending on your location.

Gradual Transition

To avoid issues, transition gradually from summer to winter diesel. Mix 70% No. 2 diesel with 30% No. 1 diesel as temperatures drop. Adjust the mix to 30% No. 2 diesel and 70% No. 1 diesel as winter sets in. In extremely cold conditions, switch entirely to No. 1 diesel.

How Do You Blend Diesel Fuel for the Winter?

Blending Ratios

Blending No. 1 and 2 diesel fuels can help achieve the desired cold weather performance. Here’s a general guideline:

  • Early Winter (Above 20°F): 70% No. 2 diesel, 30% No. 1 diesel
  • Mid-Winter (0°F to 20°F): 50% No. 2 diesel, 50% No. 1 diesel
  • Severe Winter (Below 0°F): 30% No. 2 diesel, 70% No. 1 diesel or 100% No. 1 diesel.

Considerations for Blending

  • Cloud Point: The cloud point is the temperature at which wax crystals begin to form in the fuel. No. 1 diesel has a lower cloud point than No. 2 diesel, making it more suitable for cold weather.
  • BTU Rating: No. 1 diesel has a lower energy content than No. 2 diesel, which can affect fuel efficiency. Balance the blend to maintain performance while preventing gelling.
  • Cost: No. 1 diesel is generally more expensive than No. 2 diesel. Consider the cost implications when deciding on the blend ratio.

Storage and Handling

  • Shelter Fuel Tanks: Store fuel tanks in a sheltered area to reduce heat loss and prevent wax formation.
  • Insulate Tanks and Filters: Insulating tanks, filters, and fuel lines can help maintain fuel temperature and prevent gelling.
  • Remove Water: Water in the fuel system can freeze and cause blockages. Regularly check and remove any water from the fuel tank and lines.

Additional Tips for Winter Diesel Management

Keep a Full Tank

Maintaining a full fuel tank helps prevent condensation, which can lead to water contamination in the fuel. This practice also ensures you have enough fuel in case of unexpected delays or emergencies.

Regular Maintenance

Regular maintenance is crucial for winter readiness. Check and replace engine oil with winter-grade oil, inspect glow plugs, and ensure all vehicle systems are in good working order.

Emergency Supplies

Keep emergency supplies in your truck, including a bottle of diesel additive, spare fuel filters, and basic tools. These supplies can help you address minor issues on the road and avoid costly downtime.


Managing the transition to winter-grade diesel fuel is essential for keeping your diesel-powered vehicles operational during the cold months. You can prevent common cold-weather issues such as fuel gelling and engine damage by preparing your diesel for winter, using high-quality additives, timing the switch to winter diesel correctly, and blending fuels appropriately.

Do you plan to keep your fleet on the road during winter? Be sure to start your fuel transition early. A slow diesel transition makes more economic sense and protects you from unexpected breakdowns during winter.

For expert advice and high-quality diesel products, reach out to STTC. Our team is ready to help you ensure your fleet remains on the road, no matter how harsh the winter weather gets. Contact us today to learn more about our winter diesel solutions and services.

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