What Temperature Does Diesel Freeze At?

Driving in summer can be extremely fun-filled until winter shows up. The cold temperatures during winter pose a serious challenge to virtually all vehicles, especially those with diesel engines. This is due to freezing issues.

This brings the question, “What temperature does diesel freeze at?” One of the Rxmechanic experts has captured details about the temperature level that can crystallize diesel.

Therefore, do not withdraw until you finish reading the subsequent sections of this article. Thus, you will find out the temperature level where diesel thickens and freezes in order to implement the preventive measures recommended below.

freezing point of diesel and petrol

Read Also: What Temperature Does Motor Oil Freeze and The Related Queries

What Temperature Does Diesel Freeze At?

What temperature does diesel freeze at? Diesel fuel starts freezing at 32 degrees Fahrenheit and gels around 15 degrees Fahrenheit or below. Then, the gel formation clogs the vehicle’s fuel system, making it difficult to start the engine.

The freezing issue is due to the vulnerability of the paraffin wax in diesel (especially diesel #2). Many diesel-powered vehicles can be grounded in winter due to freezing issues. This is why adequate preventive measures are very important at this point.

When diesel crystallizes in the fuel tank, it can be very frustrating. This can happen overnight in winter. Imagine waking up to an engine that will not turn over due to extremely cold temperatures. The vehicle will not only be grounded; the fuel system can suffer serious damage due to the frozen areas.

Kindly note that the freezing point of diesel and petrol differs as petrol freezes at around -100 degrees Fahrenheit. However, if you drive a gasoline or diesel-powered vehicle, be sure to implement freezing preventive measures to keep your car safe in winter.

So, it is important to do everything you can to avoid such an occurrence because remedying the situation can be costlier than preventing its occurrence in the first place.

How Do You Tell If Your Diesel Is Freezing?

When your vehicle’s diesel freezes, the occurrence comes with several obvious symptoms that let you know there’s a problem. Some of the signs that you have a frozen diesel tank include the following.

Engine start difficulty

One of the most common occurrences when diesel freezes is the difficulty in starting the vehicle’s engine. Since the gelled paraffin wax in the diesel has clogged the fuel system, it will be difficult to get the necessary fuel supply to start the engine.

The engine starts and dies.

Sometimes, if the diesel is not yet completely crystallized (at the cloud or pour point), some available liquid diesel fuel may flow through to enable the vehicle’s engine to start.

However, the engine will die down immediately or after a while due to poor fuel circulation. This may continue until you fix the issue.

Sluggish acceleration

Furthermore, if you start your car with frozen diesel fuel in the morning, you may experience sluggish acceleration as you drive. This is due to the struggle it takes the fuel system to circulate the fuel and power the vehicle.

There is no fuel pressure on the gauge

Lastly, you may also discover the absence of fuel pressure if your car has a fuel pressure gauge. Of course, the fuel pressure will be tough in a situation where the diesel in a vehicle’s tank is frozen.

Read Also: What Happens if you put Gas in a Diesel Engine?

what temp diesel freezes

How To Keep Diesel From Freezing

There are several ways to keep your truck’s diesel from freezing, depending on the methods you can apply. Some of the common hacks include the following.

Store your vehicle in a garage.

Firstly, parking outside your house during summer is quite okay. However, you may want to utilize your garage more this time around during winter because of the cold temperatures outside.

Parking inside the garage will help keep your vehicle warm and reduce the chances of the diesel freezing up overnight.

Fill up the diesel tank.

Keeping your diesel tank as full as possible (more than half full) will minimize the tendency for water condensation, which can further result in freezing.

So, you may want to top off your diesel tank as often as possible to keep it more than half full at all times.

Apply anti-gel additives 

Applying anti-gel additives in your diesel tank can also help to minimize the possibility of diesel crystallizing in cold temperatures.

Anti-gel additives or cold flow improvers are non-alcohol-based diesel fuel additives that drop the freezing point of diesel to prevent the paraffin wax from gelling during winter.

This is achieved by lowering the cold filter plugging point, which is the temperature level whereby the diesel fuel will still flow through the fuel filter.

Use winter diesel

Winter diesel is diesel #1. It does not contain the regular paraffin wax that crystallizes under cold temperatures, hence the reason why it is best during winter. So, you may want to use this type of diesel in your truck once it is winter.

Some fuel stations have winterized diesel. So, do not forget to ask at the fuel desk when to get to a fuel station for a refill.

Plug in your vehicle.

Lastly, ensure to plug in your vehicle using the engine block heater, electric blanket, etc. These components will help to keep your vehicle’s engine warm, thereby reducing the tendency for the diesel to freeze under cold temperatures.

You can install any of these devices at a dealership near you across the street. It will only cost a few bucks. However, no matter what the cost of the device is, fixing a frozen engine or fuel system can be costlier because of the extent of damage that may occur.

Therefore, it is important to do all you can to protect your vehicle from issues that can easily affect the fuel system and other components during winter.

Read Also: How Much Does a Gallon of Diesel Weigh?


How cold is too cold for diesel?

Temperature levels around 32 degrees Fahrenheit and below are too cold for diesel, as the fuel can start crystallizing once the temperature level hits that mark. When this occurs, the gel formation will gradually clog your car’s fuel system, making it difficult for the car to start.

Therefore, it is crucial to prepare for winter if you drive a diesel-engine vehicle. Using an anti-gel fuel supplement can save you the stress of battling a frozen diesel fuel system in winter.

How long does it take for diesel to freeze?

How long does it take for diesel to gel? Diesel will gradually freeze within 24 – 72 hours once the temperature level starts to drop and approaches 15 or 10 degrees Fahrenheit. The cold temperature will cause the paraffin wax in the diesel fuel to solidify gradually.

This occurrence can cause your car to be grounded because the engine will not be able to function due to the lack of fuel supply. Again, the diesel freezing point in Fahrenheit is quite different from the gasoline freezing point.

Can diesel freeze while driving?

Will diesel gel while idling or driving? The freezing process of diesel fuel goes through 3 stages – cloud point, pour point, and gel point. At the cloud point, the diesel starts to solidify with a cloudy appearance, while at the pour point, the diesel fuel loses its flow characteristics. 

Finally, at the gel point, the diesel solidifies into wax crystals that cannot flow through the fuel lines. In other words, while diesel may freeze as you drive or idle in winter, it may not get to the third stage, where the fuel solidifies.

At what temperature do I need to plug my diesel truck in?

Once temperature levels drop around -15 degrees Celsius, ensure to plug in your vehicle’s engine block heater. This will keep the engine warm irrespective of the cold weather.

If you’re asking, “At what temperature does diesel freeze in Celsius?” That’s around -12 degrees Celsius. Therefore, it is vital to play a defensive role when winter shows up. So, kindly get your engine block heater from an automotive parts shop and install it once the time comes.

Do I need to put additives in diesel in winter?

Of course, you need to put an additive in your diesel during winter to help protect the fuel from crystallizing at cold temperatures. Using an anti-gel additive can do the magic of keeping your diesel fuel system flowing in winter.

However, it would be the best to prepare ahead of time. In other words, it is crucial to know what to do if your diesel freezes. So, ensure to get the additive ready before winter comes knocking at the door.

Is cold weather bad for diesel engines?

Yes, cold weather is extremely bad for diesel engines because it will be difficult to start. Diesel engines are 5 times more difficult to start during winter than in summer. That’s why it is advisable to get an engine block heater ahead of winter.

The device will help keep your engine warm so it can easily start when you need to drive out. Generally, cold weather poses a serious challenge to vehicles.

What kind of diesel should you use in the winter?

Diesel #1 is best for winter because it is paraffin wax-free; hence the tendency of freezing is very slim. As a matter of fact, diesel #1 is also referred to as winter diesel.

The presence of paraffin wax in diesel #2 is the main reason why it freezes in winter. So, as winter shows up, you need to switch from your regular diesel #2 to diesel #1. Some of the fuel stations have a pump for winterized diesel. So, always ask to make sure.

How do I keep my diesel engine warm in the winter?

There are several ways to keep your diesel engine warm in winter. You may have to park in a garage to keep the engine warm overnight. Meanwhile, installing an engine block heater will also help sustain the engine’s heat.

Using an electric blanket, oil warmer, and battery warmer can also keep the engine heat intact for an easy start in winter. Ensure to use these components overnight on your diesel engine during winter.

Final Words

We hope to have stopped contemplating, “What temperature does diesel freeze at?” Yes, the exact point has been unveiled in this article. However, the freezing process goes through 3 different stages. Meanwhile, the 3rd stage is more complicated than the first two.

Therefore, ensure to implement the hacks recommended above to protect your vehicle’s engine and fuel system from freezing, especially during winter. You may want to find the most suitable method for you. 

However, all the strategies discussed above are easy to implement and quite affordable as well.

Learn More: 

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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