Prevent Diesel Fuel Gelling Problems in Winter

You and your staff aren’t the only ones who need looking after in cold weather – your diesel fuel needs some consideration too, in order to prevent gelling problems. In freezing temperatures, what ought to be the lifeblood of your business can instead clog your engines, cause stop-starting and prevent some engines from starting at all.

These problems are made worse by modern blend fuels, due to the sensitivity of newer engines and the high efficiency needed of filters designed to protect them.

Do you rely on fuel to keep your business running efficiently? Diesel is at particular risk from the cold weather, so it’s important to take preventative steps to avoid expensive disruption.

Follow our simple tips and you’ll be protected against diesel fuel gelling problems this winter.

Winter diesel problems explained

Winter Diesel Problems


Diesel fuel gels in cold temperatures because it contains paraffin wax – an important component that improves its viscosity and lubrication… but it’s not so great when the wax thickens as the temperature falls.

In normal temperatures, the wax is an oily liquid form in the fuel. But when the outside temperature becomes cold enough and reaches the “cloud point”, the paraffin wax begins to solidify and turns into a cloudy mixture, eventually leading to diesel fuel gelling.

If untreated, the problem will become so advanced that the wax will form crystals which can clog fuel filters and lines, stopping fuel from flowing and rendering your engine useless. This is also known as fuel starvation.


During the cold weather, free water in fuel will freeze. Ice crystals will behave like wax crystals, blocking filters and pipes, causing abrasive wear to fuel systems and preventing fuel flow.

To help avoid diesel gelling problems, its properties need to be adjusted seasonally to ensure good performance in low temperatures.

The difference between gel point and pour point in diesel fuel gelling

  • The gel point: the temperature point at which diesel turns solid and can no longer flow through the fuel lines
  • The pour point: the factor which determines the temperature at which a fluid starts to solidify; it’s the temperature at which diesel freezes. At this point, fuel will freeze solid in lines
  • The cloud point: the temperature at which paraffin creates cloudy deposits within the fuel; this varies depending on fuel characteristics but the majority of good quality fuels have a cloud point of around 32°F/0°C (untreated)
  • The cold filter plugging point (CFPP): the temperature at which crystals will rapidly plug fuel filters, starving the engine and preventing it from starting or stopping it from working

How can you recognise waxing problems?

  • If your fuel has a yellow/white deposit or cloudy appearance
  • If your engine is stuttering, stalling, damaged or fails to start at all

What can you do to help prevent diesel fuel gelling problems?

Diesel Fuel Gelling

Out with the old, in with the new

Diesel specification varies according to the season, with two separate grades for winter and summer to ensure that the fuel supply is appropriate for use.

Winter grade fuel is more resistant to cold with a minimum -12°C cold filter plugging point (CFPP min).

Summer grade fuel is only certified for use during the warmer months with a limited resistance to cold with a -4°C CFPP min. It has a higher cloud point, so it’s not suitable for use during winter where lower cloud point diesel is needed.

To avoid winter waxing, it’s important to change your fuel supply to avoid summer fuel being relied upon during winter.

We recommend that you keep your tank topped up at all times to make sure that you’re powering your equipment with the correct grade fuel. This will help keep free water out of fuel to avoid engine problems because if left untreated, water in suspension in the fuel will form ice crystals if the temperature drops below 0°C.

Only need one delivery a year? Replenish your stocks during the winter as this grade fuel can be used year-round. Call 0330 123 1144 for a reliable diesel supply within 48 hours of purchase.

Download fuel our tank maintenance checklist >>

Switch to a FAME-free renewable diesel

HVO is a renewable diesel fuel that’s 100% bio but FAME and ester-free. This avoids the instability and operability issues seen by many low-blend diesel fuels and high-blend biofuels. With a high cetane number of greater than 70 and low cold filter plugging point (CFPP) of up to -32ºC, HVO offers
superior cold start performance, clean combustion, and less chance of waxing in extreme temperatures than regular DERV.

Use the correct lubricant

Using the correct lubricants for cold weather operation will help protect engines from friction and corrosion which can lead to starting problems. If an engine oil suffers from dilution by the fuel, wax can accumulate in the lubricant and cause it to solidify in cold temperatures.

Find out more about our high-quality lubricants.

Protect your fuel supply from falling temperatures

Insulating storage fuel tanks, filters and lines on equipment and vehicles will protect them from falling temperatures and help reduce the risk of waxing and costly downtime.

  • Keep above-ground fuel tanks and handling equipment insulated to avoid excessive cooling
  • Insulate exposed pipes and pumps as they can act as radiators that quickly cool stored fuel

Beesley Fuels storage tanks are OFTEC standard and are fully compliant with all safety and environmental standards, so you can rest easy knowing your fuel stock is safe from the effects of the cold weather.

Test it, secure it

In the cold weather, it’s paramount to have your fuel stock tested frequently by an expert company. Regular fuel analysis will pick up any water present in fuel from condensation in tanks and paraffin crystals that have settled on the bottom of your fuel tank.

Add additives

Middle Distillate Flow Improvers help prevent diesel fuel gelling by stopping the paraffin wax from solidifying. A lot of cold weather additives also contribute many additional cold weather benefits like helping to improve cold engine starts and removing harmful deposits from fuel injectors.

How does Beesley Fuels help avoid winter diesel problems?

High Quality Diesel

Here at Beesley Fuels, we only supply fuel that is grade-appropriate for that season; the cloud point varies depending on the time of year. We manage diesel blends at the time of sale; however, we cannot control sporadic weather swings or fuel that is kept in storage for a long time.

Whenever you purchase diesel fuel from Beesley Fuels, whether that be in summer or winter, you can be confident in knowing that you’re at less risk of diesel fuel gelling and performance problems. Get in touch with our fuel experts today on 0330 123 1144.

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