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Diesel fuel freezes, difficult to start diesel engine when ambient temperature drops

Likely reasons:

  1. Use of diesel fuel that suits the season or does not correspond to climatic zone or standard values (large amount of paraffins). Diesel fuel freezes due to the presence of paraffins. When the temperature drops, paraffins begin to form crystals. As a result, the diesel fuel becomes unclear and stagnates. The finest crystals in paraffin clog fuel filters, settle in pipes and block the flow of fuel into the cylinders.
  2. Presence of water in diesel fuel. Water in diesel fuel can lead to a deterioration in its supply to the cylinders at low temperatures. At positive temperatures, water and fuel form an emulsion that destroys the fine filter inserts, and at negative temperatures the ice crystals that form block the fuel filters.


  1. If you are forced to use diesel fuel that does not correspond to the season, climatic zone or standard values, it is recommended to add one of the special pour point depressants to the diesel fuel before lowering the ambient temperatures:

    Application of these agents according to the instructions for use allows to lower the pour point of diesel fuel by 10…12 ºС, and the filterability limit by 8…10 ºС.

    Note: Summer diesel fuel is sometimes mixed with jet fuel, kerosene, or gasoline to lower its pour point. This can lead to cetane count reduction and engine or fuel pump bursting. In addition, the flash point of such a "winter fuel" is too low, which increases the risk of fire.
  2. To connect and remove the water in diesel fuel, periodically use one of the fuel system cleaners for diesel engines:
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