Diesel Anti Gel

There’s a lot of upsides to diesel fuel. More vehicular power, greater fuel economy, but

one of the main downsides of diesel fuel is that it does not fare well in cold weather. When temperatures drop, diesel forms crystals that clog fuel filters and fuel lines. Not only does this cause engines not to start, but it can also lead to costly repairs if engines get damaged. In extreme cold, even the best winter blend diesel fuel can reach its cloud point (the measure of diesel’s low-temperature operability) and begin to gel up. Due to so many differences in fuel quality existing across North America and the fact that each vehicle’s exposure to cold weather will be different, there is no definitive temperature in which diesel begins to gel.

However, most fuels reach their cloud point between 20 degrees F and -18 degrees F. To prevent diesel fuel from gelling (or crystallizing) you should use an anti-gel fuel supplement. Make sure to use an all-season additive or one that’s specifically designed to work well in cold climates.  Anti-gel additives are easy to use! All you do is top off your fuel tank with the treatment. Anti-gel additives drop the freezing point of diesel fuel so that it is less likely to freeze in cold temperatures. Anti-gel additives are also designed to lower the Cold Filter Plugging Point (CFPP). The CFPP is the lowest temperature at which fuel will still flow through a specific filter.

Why add anti-gel to diesel fuel?

The reason why we have to add an anti-gel additive to diesel is that diesel fuels contain wax. Normally the wax is a liquid in solution in the fuel. The problem with the wax is that this is what causes fuel to gel, and gelled fuel (or crystals) can block engine fuel filters. If the temperature is low enough then this will cause the engine to gel up completely and keep it from working at all. So why don’t we just remove the wax and skip the gelling issue altogether? Well, the reason we have the wax component is that it gives fuel a good cetane value. Cetane offers power and better engine responsiveness. Wax content is lower in the winter but remains in diesel blends for cetane.

So when should you start adding anti-gel additives to your diesel?

When temperatures are below freezing (32°F)
The rule of thumb is that the lower the temperature, the more fuel additive needs to be added. We suggest that you follow the instructions on the bottle of your anti-gel.

2. Rapid drops in temperature
If the weatherman is anticipating a cold front, you are better off adding an anti-gel additive in preparation. Preparation is key. Anti-gel additives won’t damage your engine so when in doubt use extra.

3. When you add fuel
Use an anti-gel additive whenever you fill up at the pump in the winter. Most additives can be added before or after you add fuel. We like to add beforehand to ensure good mixing.

4. When fuel begins to gel
Add an anti-gel additive as soon as possible. If your fuel is already gelled or your fuel lines are clogged up we recommend using an emergency additive that dethaws fuel and de-ices filters. These emergency treatments re-liquify fuel so that it can be combustible again.


Keeping up with this simple trick can keep your truck safe and help you avoid costly maintenance fixtures.