Technical requirements

In principle, biodiesel fuels can be used in all the engine systems that are intended for diesel use. Biodiesel fuel may also be blended with fossil diesel fuels in all proportions but caution should, however, be implemented in the following cases:

  • In case of older engines, which until now have used petroleum derived diesel fuel, biodiesel fuel may cause fuel filter clogging. The reason for the problem is that biodiesel has been known to break down deposits of residue in the fuel lines where petroleum diesel has been used and the amount of residue may exceed the cleaning capacity of the fuel filter.
  • If used over longer period of time, biodiesel may degrade the rubber parts (hoses) of the heating system in older engines and they should be replaced by the parts meant for biodiesel use. Newer engines mostly already use materials suitable for biodiesel. For more information, contact the manufacturer.

Outside temperature requirements

The cold resistance of biodiesel is mostly dependant on the source material. Without additives, biodiesel fuel tolerates temperatures from +20 C to -15C. To increase the cold resistance, special additives are used, which raise the resistance up to -30C. One way to increase the cold resistance is to add winter fossil diesel fuel to bio fuel.
In the Republic of Estonia, diesel fuel used as engine fuel must meet the standard EN 590.

In Estonia, the summer season is from May 1st to 30th September and the winter season from 1st December to 29th February. The transitional periods last from 1st October to 30th November and from 1st March to 30th April. The diesel fuel used during the transitional periods may meet either the summer or winter diesel fuel requirements. Regardless of the formal periods, the real weather conditions should always be taken into account when choosing the fuel.