Diesel gelling: How to avoid this wintertime threat to your truck

Updated Dec 22, 2023

Known for its efficiency and power, diesel fuel is the lifeblood of many vehicles and industries worldwide. However, when the temperature drops, diesel fuel can develop a problem known as gelling. This phenomenon occurs in colder weather and can wreak havoc on diesel vehicles and equipment.   

Understanding Diesel Fuel Gelling  

Diesel gelling is the result of the fuel thickening enough to turn from a liquid to a solid, a process which can begin as soon as temperatures hit 32°F (0°C). Diesel fuel is a complex mixture of hydrocarbons. At lower temperatures, these hydrocarbons can crystalize and bind together. This is more likely to happen when there is higher paraffin wax content in the fuel. When wax crystals form, they can block fuel filters and restrict the flow of diesel fuel to the engine, causing several problems for diesel vehicles.  

Effects of Diesel Fuel Gelling on Diesel Vehicles 

  • Engine Stalling: The most severe cases of fuel gelling can cause your engine to stall or prevent it from starting altogether, leaving you stranded in the cold. Starting or restarting a gelled engine can be a challenging and time-consuming affair. It will likely require heating components that may not be readily available. 
  • Engine Power Loss: As wax crystals clog the fuel lines and filters, the engine receives less fuel, resulting in reduced power and performance. This can be especially problematic in situations where you need maximum engine power, such as during acceleration or when hauling heavy loads.
  • Reduced Fuel Efficiency: When the engine doesn't receive an adequate supply of fuel due to gelling, it must work harder to maintain its performance, which can result in reduced fuel efficiency. This means more frequent trips to the pump and higher operating costs.  
  • Fuel System Damage: The solidified wax crystals can damage fuel system components, including fuel pumps and injectors. These repairs can be expensive and require excess downtime, making diesel fuel gelling a costly issue for vehicle owners. 
  • Increased Costs: Gelling may cause the need for premature fuel filter replacement or even a tow. Both are expensive solutions to a problem that can easily be avoided. 

3 Easy Steps to Preventing Diesel Fuel Gelling  

Preventing diesel fuel gelling is crucial for the smooth operation of diesel vehicles, especially in colder climates. Here are some strategies to prevent gelling: 

  • Keep Fuel Tanks Full: Keeping your diesel fuel tank full reduces the air space inside the tank, minimizing condensation and water content, which can help prevent gelling.  
  • Use Winter-Blend Diesel Fuel: Winter-blend diesel fuel may contain additives designed to lower the gelling point of the fuel or contain a blend of No2 diesel and No1 diesel. Both make it less susceptible to cold weather conditions. You should note that while winter-blend diesel fuel may be treated with fuel additives, the type and amount aren’t necessarily clear. Treating with your own additives will eliminate that guesswork.
  • Add Anti-Gelling Additives: Quality anti-gel additives lower the Cold Filter Plugging Point (CFPP) of diesel, the lowest temperature fuel will flow through a specific filter. It prevents the fuel from freezing even in extreme cold. Howes makes a full line of diesel additives, including Howes Diesel Treat, a guaranteed anti-gel and fuel conditioner.    

How to Handle a Gelling Emergency 

Despite preventive efforts, there may be instances when diesel fuel gelling occurs. In these situations, immediate action is necessary to restore the fuel’s flow.  

  • Emergency Fuel Additives: There are specific emergency additives, often called “fuel thaws” or “emergency reliquefiers,” that can help reliquefy gelled fuel. The additives are designed to dissolve the wax crystals that have formed and get the diesel flowing again. Howes Diesel Lifeline is the only emergency product that doesn’t use alcohol or harmful solvents to combat gelled fuel.  

For more information on all Howes products, visit a travel center near you or howesproducts.com.   

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