#1 Vs. #2 Diesel: What's The Difference?

It may seem pretty straightforward to pull up to the gas station and fill up your pickup with diesel fuel, but chances are you've noticed that some gas stations offer diesel #1 and diesel #2. There are some key differences between these two fuel types that make them both useful for different driving conditions. 

Diesel #1 and diesel #2 have distinct characteristics that may make one more suitable than the other for your driving needs. For example, diesel #1 has a lower sulfur content that makes it inherently cleaner, boasts a lower viscosity or thickness, and a higher cetane number, all of which contribute to a hotter burn. This gives your engine a smoother and quicker start while its lower viscosity maintains a better fuel flow, making diesel #1 a great choice for driving in colder climates. However, diesel #2 has a lower cetane number and reduced flammability, meaning it burns slower. This makes diesel #2 a lot better for long drives where you want better mileage and don't want to make frequent pit stops.

While using either diesel won't likely damage your engine or vehicle, there are some things to consider when choosing between either option. For example, you may want to consider diesel #1 if you tend to start your diesel engine in cold weather climates. Diesel #2 is more compatible with general-purpose engines that aren't made for heavy-duty tasks in harsh climates. 

The second thing to keep in mind is the weather you'll be driving in after fueling up. Diesel #1 is thinner, improves ignition quality, reduces friction with added lubricants, and has properties that prevent the fuel from gelling, or the process of paraffin wax particles solidifying in the fuel. This makes it the more popular choice for driving in cold temperatures. Diesel #2's thickness makes it better for warmer temperatures or if you live in an area that at least remains above 40 degrees Fahrenheit throughout the year. Since most regions are above that temperature during most of the year, it's easier to find diesel #2 in a lot of countries. 

Another factor when choosing your diesel fuel is the cost. Diesel #1 is often more expensive than diesel #2 due to its additives. You'll also need to fuel up more often with diesel #1, meaning more stops at the gas station. Diesel #1 is still more efficient than gas, however.