Types of Diesel Fuel?

There are three commonly recognized types of diesel fuel: 1D, 2D, and 4D. The distinctions are pour rate (the lowest temperature a liquid will pour) and viscosity (the resistance of a liquid to flowing). 1D has a lower viscosity and pour rate is therefore used primarily in colder climates. 2D is higher viscosity and pour rate and is used in warmer climates. 4D is used primarily for marine and in stationary engines where temperature is not an issue. For more information, look here: