What Happens to Diesel Fuel in Cold Weather?

January 30, 2024

What Happens to Diesel Fuel in Cold Weather? Everything you need to know

A basic understanding of what happens to diesel fuel in cold weather is essential for maintaining the diesel engine's performance during winter. Cold temperatures can cause diesel fuel to form crystals. These crystals form clogs in filters and fuel lines, hindering engine operation. 

When you understand how diesel reacts to the cold, you can take proactive measures to prevent such issues and safeguard your vehicles. Whether you manage a fleet or own diesel-powered vehicles, knowing these effects is critical to ensuring trouble-free transportation in winter.

How Does Cold Weather Affect Diesel Fuel?

In cold countries, diesel equipment owners often experience a decline in diesel engine performance as temperature decreases. As the temperature drops, diesel fuel contracts by about 0.85 ml per liter. This contraction can significantly affect fuel storage, transportation, and engine combustion.

When the weather gets cold, the free water molecules in the fuel become ice crystals due to their low freezing point. The resulting ice crystals act like solid particles and accumulate in filters, causing wear to fuel systems. The substantial amounts of these solid ice crystals can also disrupt fuel flow. 

cold weather diesel fuel

Here are some cold-related challenges that collectively affect the overall efficiency and starting capability of diesel engines in winter. 

  • Paraffin wax solidifies in diesel fuel and leads to filter blockages.
  • Cold temperatures increase diesel fuel viscosity. It results in filter clogs, reduced fuel flow, and engine damage.
  • Extremely low temperature triggers the cloud point, where wax crystals form. It causes fuel cloudiness.
  • Low temperature causes diesel fuel oxidation, resulting in gum and varnish deposits. 
  • Cold weather also induces diesel fuel instability, leading to the formation of insoluble particles and sediments.

Diesel Fuel Gelling

Diesel fuel contains paraffin wax, which helps with lubrication and viscosity. The wax thickens into tiny crystals in freezing temperatures, causing immense problems. Diesel fuel can gel, especially around 14-15 degrees Fahrenheit

cold weather diesel

Symptoms of Diesel Fuel Gelling

Recognizing signs of diesel fuel gelling is crucial for maintaining engine performance. These symptoms include:

  • A cloudy appearance in the fuel
  • Sputtering engine
  • Difficulty in engine ignition
  • Inconsistent running performance of a vehicle
  • The emission of white smoke during acceleration 
  • Sluggish acceleration with variations in fuel rail pressure.

How to Prevent?

Understanding how to prevent diesel fuel gelling is critical for optimal engine performance. 

Here are the precautions you must follow to avoid the thickening of diesel fuel in cold weather.

  • Use high-quality cold-weather diesel additives to prevent fuel thickening.
  • Choose effective fuel treatments and additives that inhibit wax crystallization.
  • Use premium winterized fuel with anti-gelling properties.
  • Change fuel filters ahead of winter.
  • Insulate your fuel tank, filters, and fuel lines to protect against cold temperatures.
  • Regularly inspect your engine and replace glow plugs as needed.

Wax Crystal Formation

Wax crystal formation in diesel fuel refers to the process where a small percentage of paraffin wax in the fuel solidifies under lower temperature conditions, particularly during winter. This wax benefits in mild to high temperatures, enhancing engine power and fuel efficiency. However, it undergoes crystallization in colder temperatures, causing it to thicken and negatively impacting the fuel. 

diesel fuel for winter

If temperatures drop significantly and enough wax crystallizes, fuel flow slows down. It eventually leads to potential blockages in fuel lines and filters. Consequently, it disrupts delivery and transportation services by impeding the standard engine functioning.

As you know what happens to diesel fuel in cold weather, you must know measures to tackle such issues. You can use anti-waxing additives to boost fuel resistance and cater to wax crystal formation. 

Cold Weather Additives

Some diesel-fuel treatments also incorporate additives and modifiers that help prevent the formation of problematic wax crystals. These high-performance additives effectively combat gelling by dispersing wax crystals. They prevent larger crystals' growth by reducing their size and diminishing their accumulation in the vehicle engine. It ensures a smoother flow of diesel fuel in cold weather, leading to seamless engine performance.

Diesel fuel additives for cold weather play a central role in overcoming challenges such as fuel gelling and wax crystal formation. They are designed to improve the efficiency and reliability of diesel engines in cold temperatures. Key types of diesel fuel additives include the following:

  • Flow improvers
  • Wax anti-settling additives
  • Cloud point depressants
  • De-icing additives
  • Anti-gel additives

Using cold weather additives is straightforward. Begin by reading the instructions on the additive container. Pour the recommended amount directly into the fuel tank and drive a short distance to ensure thorough mixing. Use it whenever you fill your tank and add more as necessary.

Winter Diesel Fuel Blends

Winter diesel fuel blend is a combination of No.1 and No.2 diesel fuels designed to prevent gelling in cold temperatures. Unlike regular diesel fuel, it offers lower viscosity and higher resistance to gelling, making it well-suited for use in winter.

diesel in the winter

To use winter diesel blends effectively in the cold, ensure your vehicle’s compatibility with that particular diesel blend by checking the manufacturer's suggestions. Prioritize using the blend when your vehicle will be parked in the cold for an extended period to prevent fuel gelling during storage. 

Moreover, follow the fuel manufacturer's guidelines about the blend ratio. Some blends have additives, so pay attention to recommendations for better performance in chilly weather.

Preparing Your Diesel Engine for Cold Weather

A diesel engine differs significantly from a typical gasoline-powered vehicle, requiring specific knowledge for proper maintenance. You must regularly change the oil, check fluid levels, and inspect the oil filters to keep your diesel engine in good shape. 

diesel vs gasoline

Using the correct fuel and adding a fuel stabilizer before storage is another best diesel fuel maintenance practice for winter. To detect and address water issues, sample your fuel weekly for effective winter fuel management. The crucial step involves draining and removing all free water to prevent freezing.

Besides that, one must also adhere to the following fuel system precautions and maintenance practices to avoid undue issues with diesel fuel in cold weather:

  • Use effective fuel system cleaners.
  • Ensure your vehicle has the correct coolant level
  • Opt for winter blended diesel
  • Choose a thinner engine oil
  • Preheat the engine before starting.

Cold Weather Driving Tips

Conducting a thorough vehicle check is essential before starting an extended journey with a diesel-powered vehicle for transportation or delivery. The fleet owners and drivers must address potential fuel-related issues to ensure a smooth and trouble-free travel experience. 

what diesel to use in winter

For fleet drivers navigating trailers and trucks in winter, it's crucial to prioritize safe driving practices. Follow these driving tips for a hassle-free and safe driving venture in harsh winters:

  • Use snow tires for better winter performance.
  • Accelerate or decelerate slowly to avoid skids. 
  • Increase your following distance to five to six seconds for extended braking distances. 
  • Avoid unnecessary stops if possible.
  • Refrain from accelerating your vehicle when approaching hills.
  • Avoid stopping while ascending a hill to prevent tires from slipping.

FAQ - Frequently Asked Questions

What is the best diesel for winter?

The best diesel for winter is Diesel #1, also known as winter diesel. It outperforms Diesel #2 in cold temperatures due to its lower viscosity. In addition, it is less prone to gelling in freezing conditions.

How do I prepare my diesel for winter?

To winterize your diesel vehicle, use winter-grade oil for improved engine lubrication, check and ensure the battery is in good condition, and test the functionality of glow plugs. You must also inspect the exhaust system for blockages and add anti-gel additives to prevent fuel gelling in cold temperatures.

How do you treat diesel for winter?

Using an anti-gel fuel supplement is recommended to treat diesel for winter. The anti-gel additives effectively lower the freezing point of diesel fuel, reducing the likelihood of crystallization and freezing in cold temperatures.

What do you add to diesel fuel in winter?

One can add anti-gel supplements or anti-freezing additives to diesel fuel in winter. These help lower the viscosity of diesel fuel and prevent it from freezing.

What grade of diesel fuel would be commonly used in cold climates?

In cold climates, a commonly used grade of diesel fuel is 1D (or Diesel #1), designed explicitly for cold weather operations. This fuel has a lower viscosity and a reduced pour point, making it well-suited for colder temperatures.

What happens to diesel fuel when it gets cold?

When diesel fuel gets cold, it transforms into a dense, waxy substance that loses its ability to flow through filters. This phenomenon is commonly referred to as "gelling."

Can I mix winter and summer diesel?

Mixing winter and summer diesel won't be beneficial. In fact, blending them might weaken the cold resistance of winter fuel, making it less effective in colder temperatures. 

How do you prevent diesel fuel from gelling?

You can use good-quality cold-weather additives to stop diesel fuel from getting thick in cold weather. These additives help keep the fuel from thickening, ensuring it stays fluid and runs smoothly in colder temperatures.

How do you know if your diesel is gelling?

Signs of diesel gelling include cloudy fuel, a sputtering engine, ignition issues, inconsistent vehicle performance, and white smoke during acceleration.

What happens if you put too much additives in diesel fuel?

Putting more than the approved amount of additives in diesel fuel can cause problems, such as clogged filters and a drop in overall engine performance and efficiency.

What is the most common cause of diesel gelling problems in cold weather?

The main reason for diesel gelling in cold weather is the impact of temperature on a diesel fuel component called paraffin. Paraffin is flammable and adds power to the engine when burned. But, when it gets cold, diesel solidifies, leading to gelling issues.

What are some tips for choosing the right cold-weather fuel?

When picking cold-weather fuel, consider the cloud point, the temperature at which the fuel appears cloudy. Many companies offer different cloud point options for different seasons and regions in the U.S. You can choose the right one for your blend depending on the time of year.

Does Cold Weather Affect Fuel Economy

Cold weather significantly impacts winter fuel economy, decreasing the efficiency and performance of internal combustion engines as temperatures drop. We cover the various factors that affect you here in our article.

Connect with Fuel Logic to Solve Fuel-Related Headaches in Cold Weather

As we approach the challenging winter months, fuel-related challenges become more apparent for fleet owners and those in transportation services. We have shared cautionary notes for fleet owners and transportation managers, offering valuable insights to avoid missteps during winter operations. 

So, taking proactive steps, including utilizing cold-weather diesel additives and following recommended maintenance practices, becomes vital. We are here to assist you in every aspect of fuel-related challenges, and our services are just a contact away. Reach out for any assistance you may need.

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