All flexible-fuel vehicles in Sweden use an E75 winter blend instead of E85 to avoid engine starting problems during cold weather. This blend was introduced since the winter 2006-07 and E75 is used from November until March. For temperature below E85 flex vehicles require an engine block heater. The use of this device is also recommended for gasoline vehicles when temperatures drop below . Another option when extreme cold weather is expected is to add more pure gasoline in the tank, thus reducing the ethanol content below the E75 winter blend, or simply not to use E85 during extreme low temperature spells.