 All diesel fuels contain wax molecules. These are natural components of the crude oil that diesel is produced from. Wax is considered an important diesel component because of its high cetane value (for good ignition quality of the fuel). However, in severe winter conditions especially in inland or high country areas the diesel may get cold enough for the wax starts to crystallise (solidify). If enough wax crystals solidify the fuel lines, filters and strainers in diesel powered engines and machinery may become blocked and as a result may become difficult or impossible to operate. This phenomenon is known as “waxing” In New Zealand the legal specification for diesel varies seasonally. In winter, fuel manufacturers are required to produce diesel where the temperature at which wax crystals begin to form is lowered. This reduces the likelihood of waxing occurring. It is therefore important that in winter you use winter grade fuel. For further information and advice, call our Technical Helpline 0800 4 SHELL Or email our Technical support team For more details on how prevent waxing affecting your business, download a copy of our brochure “Diesel Fuel in Winter”. | 
