Diesel fuel additives from reputable brands use the same chemical-based additives from the refinery. Unlike gasoline, diesel is a lesser-refined fuel prone to molecular changes when exposed to temperature changes and prolonged storage — hence the need for additives to stabilize the diesel.
Moreover, diesel fuel contains a small percentage of dissolved water measured in parts per million (ppm). Too much water causes problems like fouled injectors, poor combustion, and blocked fuel lines due to frozen fuel in icy weather. Pouring a bottle of diesel fuel additive removes suspended water from the fuel and prevents the diesel from coagulating in winter.
In addition, diesel additives contain detergents to keep the injectors clean, while some have ingredients to boost the cetane number for smoother idling and easier cold starts. Diesel additives could provide a slight performance upgrade depending on the product, but their primary goal is to clean the injectors, remove water, add lubrication, and improve the diesel’s thermal stability.
Diesel fuel additives are not a magic do-all product. However, the water-removing and anti-freezing benefits are worth the extra penny no matter what truck you drive or where you live.
